Exhibit 3.6(b)

                            CERTIFICATE OF AMENDMENT

                                  OF BYLAWS OF

                            ALBERTA INVESTMENTS, INC.

     The undersigned, being the duly elected, qualified and acting Secretary of
Alberta Investments, Inc., a Texas corporation, and the keeper of the minutes
and records of said corporation, does hereby certify that the following is a
true and correct copy of the amendments to the Bylaws of this corporation as
adopted by a meeting of the Shareholders and Directors on April 17, 1985:

          RESOLVED, that a new section 3.15 of Article Three be added which will
     read as follows:

          "3.15. The Board of Directors may appoint any and all committees to
     consist of members of the Board of Directors, and the Board of Directors
     may delegate their powers and authority to any such committee limited only
     by the provisions of Article 2.36 of the Texas Business Corporation Act as
     it now exists or may be modified hereafter."

          FURTHER RESOLVED that Article 3.02 of the Bylaws of the corporation
     be, and it is hereby amended so that it will hereafter read as follows:

          "The authorized number of Directors of this corporation shall be eight
     (8). The Directors need not be shareholders of this corporation or
     residents of Texas. The number of Directors may be increased or decreased
     from time to time by amendment to these Bylaws, but no decrease shall have
     the effect of shortening the term of any incumbent Director. Any
     directorship to be filled by reason of an increase in the number of
     Directors shall be filled by election at an annual meeting or at a special
     meeting of shareholders called for that purpose."

          FURTHER RESOLVED that Article 2.02 of the Bylaws of the corporation
     be, and it is hereby amended so that it will hereafter read as follows:

          "The annual meetings of the shareholders shall be held each year at
     anytime set by the Board of Directors within six (6) months following the
     closing of the corporation's fiscal year end."

          TO CERTIFY WHICH, witness my hand this 17th day of April, 1985.


                                        /s/ Christopher G. Sharp
                                        ----------------------------------------
                                        Christopher G. Sharp, Secretary