SCHEDULE 13G

                                (Rule 13d-102)

 Information to be Included in Statements Filed Pursuant to Rule 13d-1(b), (c)
         and (d) and Amendments Thereto Filed Pursuant to Rule 13d-2.

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                   Under the Securities Exchange Act of 1934
                              (Amendment No.   )*


                            Comstock Resources Inc
- --------------------------------------------------------------------------------
                               (Name of Issuer)


                                 Common Stock
- --------------------------------------------------------------------------------
                        (Title of Class of Securities)

                                   205768203
                      ----------------------------------
                                (CUSIP Number)

                               December 31, 2010
                  ------------------------------------------
            (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

                               [X] Rule 13d-1(b)

                               [_] Rule 13d-1(c)

                               [_] Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a reporting person's
  initial filing on this form with respect to the subject class of securities,
  and for any subsequent amendment containing information which would alter the
  disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).

                                 Page 1 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     Artisan Partners Holdings LP
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     HC
- --------------------------------------------------------------------------------

                                 Page 2 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     Artisan Investment Corporation
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     Wisconsin
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     HC
- --------------------------------------------------------------------------------

                                 Page 3 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     Artisan Partners Limited Partnership
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     IA
- --------------------------------------------------------------------------------

                                 Page 4 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     Artisan Investments GP LLC
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     HC
- --------------------------------------------------------------------------------

                                 Page 5 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     ZFIC, Inc.
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     Wisconsin
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     HC
- --------------------------------------------------------------------------------

                                 Page 6 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     Andrew A. Ziegler
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     U.S.A.
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     IN
- --------------------------------------------------------------------------------

                                 Page 7 of 16




CUSIP No.  205768203                        13G

- --------------------------------------------------------------------------------
 1  NAME OF REPORTING PERSON

     Carlene M. Ziegler
- --------------------------------------------------------------------------------
 2  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    (see Instructions)                                                   (a) [_]
                                                                         (b) [_]

     Not Applicable
- --------------------------------------------------------------------------------
 3  SEC USE ONLY

- --------------------------------------------------------------------------------
 4  CITIZENSHIP OR PLACE OF ORGANIZATION

     U.S.A.
- --------------------------------------------------------------------------------
                5  SOLE VOTING POWER

 NUMBER OF          None
   SHARES       ---------------------------------------------------------------
BENEFICIALLY    6  SHARED VOTING POWER
  OWNED BY
    EACH             2,643,290
 REPORTING      ---------------------------------------------------------------
   PERSON       7  SOLE DISPOSITIVE POWER
    WITH
                    None
                ---------------------------------------------------------------
                8  SHARED DISPOSITIVE POWER

                    2,771,890
- -------------------------------------------------------------------------------
 9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,771,890
- --------------------------------------------------------------------------------
10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
    (see Instructions)                                                       [_]

     Not Applicable
- --------------------------------------------------------------------------------
11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     5.9%
- --------------------------------------------------------------------------------
12  TYPE OF REPORTING PERSON
    (see Instructions)

     IN
- --------------------------------------------------------------------------------

                                 Page 8 of 16



Item 1(a)   Name of Issuer:

              Comstock Resources Inc

Item 1(b)   Address of Issuer's Principal Executive Offices:

              5300 Town and Country Blvd, Suite 500, Frisco, TX 75034

Item 2(a)   Name of Person Filing:

              Artisan Partners Holdings LP ("Artisan Holdings")
              Artisan Investment Corporation, the general partner of
                 Artisan Holdings ("Artisan Corp.")
              Artisan Partners Limited Partnership ("Artisan Partners")
              Artisan Investments GP LLC, the general partner of
                 Artisan Partners ("Artisan Investments")
              ZFIC, Inc., the sole stockholder of Artisan Corp. ("ZFIC")
              Andrew A. Ziegler
              Carlene M. Ziegler

Item 2(b)   Address of Principal Business Office:

              Artisan Holdings, Artisan Corp., Artisan Partners, Artisan
              Investments, ZFIC,
              Mr. Ziegler and Ms. Ziegler are all located at:

              875 East Wisconsin Avenue, Suite 800
              Milwaukee, WI 53202

Item 2(c)   Citizenship:

              Artisan Holdings is a Delaware limited partnership
              Artisan Corp. is a Wisconsin corporation
              Artisan Partners is a Delaware limited partnership
              Artisan Investments is a Delaware limited liability company
              ZFIC is a Wisconsin corporation
              Mr. Ziegler and Ms. Ziegler are U.S. citizens

Item 2(d)   Title of Class of Securities:

              Common Stock

Item 2(e)   CUSIP Number:

              205768203

Item 3      Type of Person:

              (e) Artisan Partners is an investment adviser registered under
              section 203 of the Investment Advisers Act of 1940; Artisan
              Holdings is the sole limited partner of Artisan Partners; Artisan
              Investments is the general partner of Artisan Partners; Artisan
              Corp is the general partner of Artisan Holdings; ZFIC is the sole
              stockholder of Artisan Corp.; Mr. Ziegler and Ms. Ziegler are the
              principal stockholders of ZFIC.

                                 Page 9 of 16



Item 4    Ownership (at December 31, 2010):

              (a)  Amount owned "beneficially" within the meaning of rule 13d-3:

                   2,771,890

              (b)  Percent of class:

                   5.9% (based on 47,317,356 shares outstanding as of November
                   4, 2010)

              (c)  Number of shares as to which such person has:

                   (i)    sole power to vote or to direct the vote:

                          None

                   (ii)   shared power to vote or to direct the vote:

                          2,643,290

                   (iii)  sole power to dispose or to direct the disposition of:

                          None

                   (iv)   shared power to dispose or to direct the disposition
                          of:

                          2,771,890

Item 5      Ownership of Five Percent or Less of a Class:

              Not Applicable

Item 6      Ownership of More than Five Percent on Behalf of Another Person:

              The shares reported herein have been acquired on behalf of
              discretionary clients of Artisan Partners. Persons other than
              Artisan Partners are entitled to receive all dividends from, and
              proceeds from the sale of, those shares. None of those persons,
              to the knowledge of Artisan Partners, Artisan Holdings, Artisan
              Investments, Artisan Corp., ZFIC, Mr. Ziegler or Ms. Ziegler, has
              an economic interest in more than 5% of the class.

Item 7      Identification and Classification of the Subsidiary Which Acquired
            the Security Being Reported on by the Parent Holding Company or
            Control Person:

              Not Applicable

Item 8      Identification and Classification of Members of the Group:

              Not Applicable

Item 9      Notice of Dissolution of Group:

              Not Applicable

Item 10      Certification:

              By signing below I certify that, to the best of my knowledge and
              belief, the securities referred to above were acquired and are
              held in the ordinary course of business and were not acquired and
              are not held for the purpose of or with the effect of changing or
              influencing the control of the issuer of the securities and were
              not acquired and are not held in connection with or as a
              participant in any transaction having that purpose or effect.

                                 Page 10 of 16



                                   Signature

   After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Date: February 10, 2011

                                     ARTISAN INVESTMENT CORPORATION,
                                     for itself and as the general partner of
                                     ARTISAN PARTNERS HOLDINGS LP

                                     By:  Janet D. Olsen*
                                          ------------------------------------

                                     ARTISAN INVESTMENTS GP LLC,
                                     for itself and as the general partner of
                                     ARTISAN PARTNERS LIMITED PARTNERSHIP

                                     By:  Janet D. Olsen*
                                          ------------------------------------

                                     ZFIC, INC.

                                     By:  Janet D. Olsen*
                                          ------------------------------------

                                     ANDREW A. ZIEGLER

                                     Andrew A. Ziegler*
                                     -----------------------------------------

                                     CARLENE M. ZIEGLER

                                     Carlene M. Ziegler*
                                     -----------------------------------------

                                     *By:  /s/ Janet D. Olsen
                                           -----------------------------------
                                           Janet D. Olsen
                                           Vice President of Artisan
                                             Investment Corporation
                                           Vice President of Artisan
                                             Investments GP LLC
                                           Attorney-in-Fact for ZFIC, Inc.
                                           Attorney-in-Fact for Andrew A.
                                             Ziegler
                                           Attorney-in-Fact for Carlene M.
                                             Ziegler

                                 Page 11 of 16



                                 Exhibit Index

Exhibit 1    Joint Filing Agreement dated February 10, 2011 by and among
             Artisan Partners Holdings LP, Artisan Investment Corporation,
             Artisan Partners Limited Partnership, Artisan Investments GP LLC,
             ZFIC, Inc., Andrew A. Ziegler and Carlene M. Ziegler

Exhibit 2    Power of Attorney of ZFIC, Inc., dated March 19, 2007

Exhibit 3    Power of Attorney of Andrew A. Ziegler dated March 19, 2007

Exhibit 4    Power of Attorney of Carlene M. Ziegler dated March 19, 2007

                                 Page 12 of 16



                                                                      EXHIBIT 1

                            JOINT FILING AGREEMENT

   The undersigned hereby agree to the joint filing of the Schedule 13G to
which this Agreement is attached.

       Dated: February 10, 2011

                                     ARTISAN INVESTMENT CORPORATION,
                                     for itself and as the general partner of
                                     ARTISAN PARTNERS HOLDINGS LP

                                     By:  Janet D. Olsen*
                                          ------------------------------------

                                     ARTISAN INVESTMENTS GP LLC,
                                     for itself and as the general partner of
                                     ARTISAN PARTNERS LIMITED PARTNERSHIP

                                     By:  Janet D. Olsen*
                                          ------------------------------------

                                     ZFIC, INC.

                                     By:  Janet D. Olsen*
                                          ------------------------------------

                                     ANDREW A. ZIEGLER

                                     Andrew A. Ziegler*
                                     -----------------------------------------

                                     CARLENE M. ZIEGLER

                                     Carlene M. Ziegler*
                                     -----------------------------------------

                                     *By:  /s/ Janet D. Olsen
                                           -----------------------------------
                                           Janet D. Olsen
                                           Vice President of Artisan
                                             Investment Corporation
                                           Vice President of Artisan
                                             Investments GP LLC
                                           Attorney-in-Fact for ZFIC, Inc.
                                           Attorney-in-Fact for Andrew A.
                                             Ziegler
                                           Attorney-in-Fact for Carlene M.
                                             Ziegler

                                 Page 13 of 16



                                                                      EXHIBIT 2

                               POWER OF ATTORNEY

   The undersigned, ZFIC, Inc., hereby appoints Lawrence A. Totsky, Janet D.
Olsen, and Sarah A. Johnson, and each of them individually, its true and lawful
attorney-in-fact and agent, with full power to execute and file with the United
States Securities and Exchange Commission and any stock exchange or similar
authority, for and on its behalf in any and all capacities, any and all reports
required to be filed pursuant to Section 13 of the Securities Exchange Act of
1934 and the rules thereunder, including but not limited to reports on Schedule
13D or 13G, any and all amendments to such reports, with all exhibits, and any
other forms or documents as may be necessary in connection with the filing of
such reports with the United States Securities and Exchange Commission and any
stock exchange or similar authority, granting unto said attorney full power and
authority to do and perform any and all acts for and on behalf of the
undersigned which may be necessary or desirable to complete, as fully as the
undersigned might or could do in person.

   This Power of Attorney shall remain in full force and effect until revoked
by the undersigned in a signed writing delivered to the foregoing
attorneys-in-fact and agents.

   IN WITNESS WHEREOF the undersigned has caused this Power of Attorney to be
executed this 19th day of March, 2007.

                                             ZFIC, INC.

                                             By:  /s/ Andrew A. Ziegler
                                                  ------------------------------
                                                  Andrew A. Ziegler
                                                  Vice President

STATE OF WISCONSIN )
                   ) SS.
COUNTY OF MILWAUKEE)

   I, Timothy K. Weston, a Notary Public in and for the County of Milwaukee,
State of Wisconsin, DO HEREBY CERTIFY that Andrew A. Ziegler, who is personally
known to me to be the same person whose name is subscribed to the foregoing
instrument, appeared before me this day in person and acknowledged that he
signed and delivered the said instrument as his own free and voluntary act, for
the uses and purposes therein set forth.

   Given under my hand and notarial seal, this 19th day of March, 2007.

                                                  /s/ Timothy K. Weston
                                                  ------------------------------
                                                  Notary Public

                                 Page 14 of 16



                                                                      EXHIBIT 3

                               POWER OF ATTORNEY

   The undersigned, Andrew A. Ziegler, hereby appoints Lawrence A. Totsky,
Janet D. Olsen, and Sarah A. Johnson, and each of them individually, his true
and lawful attorney-in-fact and agent, with full power to execute and file with
the United States Securities and Exchange Commission and any stock exchange or
similar authority, for and on his behalf in any and all capacities, any and all
reports required to be filed pursuant to Section 13 of the Securities Exchange
Act of 1934 and the rules thereunder, including but not limited to reports on
Schedule 13D or 13G, any and all amendments to such reports, with all exhibits,
and any other forms or documents as may be necessary in connection with the
filing of such reports with the United States Securities and Exchange
Commission and any stock exchange or similar authority, granting unto said
attorney full power and authority to do and perform any and all acts for and on
behalf of the undersigned which may be necessary or desirable to complete, as
fully as the undersigned might or could do in person.

   This Power of Attorney shall remain in full force and effect until revoked
by the undersigned in a signed writing delivered to the foregoing
attorneys-in-fact and agents.

   IN WITNESS WHEREOF the undersigned has caused this Power of Attorney to be
executed this 19th day of March, 2007.

                                                  /s/ Andrew A. Ziegler
                                                  ------------------------------
                                                  Andrew A. Ziegler

STATE OF WISCONSIN )
                   ) SS.
COUNTY OF MILWAUKEE)

   I, Timothy K. Weston, a Notary Public in and for the County of Milwaukee,
State of Wisconsin, DO HEREBY CERTIFY that Andrew A. Ziegler, who is personally
known to me to be the same person whose name is subscribed to the foregoing
instrument, appeared before me this day in person and acknowledged that he
signed and delivered the said instrument as his own free and voluntary act, for
the uses and purposes therein set forth.

   Given under my hand and notarial seal, this 19th day of March, 2007.

                                                  /s/ Timothy K. Weston
                                                  ------------------------------
                                                  Notary Public

                                 Page 15 of 16



                                                                      EXHIBIT 4

                               POWER OF ATTORNEY

   The undersigned, Carlene M. Ziegler, hereby appoints Lawrence A. Totsky,
Janet D. Olsen, and Sarah A. Johnson, and each of them individually, her true
and lawful attorney-in-fact and agent, with full power to execute and file with
the United States Securities and Exchange Commission and any stock exchange or
similar authority, for and on her behalf in any and all capacities, any and all
reports required to be filed pursuant to Section 13 of the Securities Exchange
Act of 1934 and the rules thereunder, including but not limited to reports on
Schedule 13D or 13G, any and all amendments to such reports, with all exhibits,
and any other forms or documents as may be necessary in connection with the
filing of such reports with the United States Securities and Exchange
Commission and any stock exchange or similar authority, granting unto said
attorney full power and authority to do and perform any and all acts for and on
behalf of the undersigned which may be necessary or desirable to complete, as
fully as the undersigned might or could do in person.

   This Power of Attorney shall remain in full force and effect until revoked
by the undersigned in a signed writing delivered to the foregoing
attorneys-in-fact and agents.

   IN WITNESS WHEREOF the undersigned has caused this Power of Attorney to be
executed this 19th day of March, 2007.

                                                  /s/ Carlene M. Ziegler
                                                  ------------------------------
                                                  Carlene M. Ziegler

STATE OF WISCONSIN )
                   ) SS.
COUNTY OF MILWAUKEE)

   I, Timothy K. Weston, a Notary Public in and for the County of Milwaukee,
State of Wisconsin, DO HEREBY CERTIFY that Carlene M. Ziegler, who is
personally known to me to be the same person whose name is subscribed to the
foregoing instrument, appeared before me this day in person and acknowledged
that she signed and delivered the said instrument as her own free and voluntary
act, for the uses and purposes therein set forth.

   Given under my hand and notarial seal, this 19th day of March, 2007.

                                                  /s/ Timothy K. Weston
                                                  ------------------------------
                                                  Notary Public

                                 Page 16 of 16