EXHIBIT 3.15

                            ARTICLES OF INCORPORATION
                                       OF
                             HANOVER ENERGY COMPANY

                                        I

         The name of the corporation is Hanover Energy Company.

                                       II

         The purpose of the corporation is to engage in any lawful act or
activity for which a corporation may be organized under the General Corporation
Law of California other than a banking business, the trust company business or
the practice of a profession permitted to be incorporated by the California
Corporations Code.

                                       III

         The name and address in the State of California of the corporation's
initial agent for service of process are:

                                 Alan M. Fenning
                      18872 MacArthur Boulevard, Suite 400
                            Irvine, California 92715

                                       IV

         This corporation is authorized to issue only one class of shares, which
shall be designated "common" shares. The total authorized number of such shares
authorized to be issued is ten thousand (10,000) shares.

                                        V

         1.       The liability of directors of the corporation for monetary
damages shall be eliminated to the fullest extent permissible under California
law.

         2.       The corporation is authorized to provide indemnification of
agents (as defined in Section 317 of the California Corporations Code) through
bylaw provisions, agreements with agents, vote of shareholders or disinterested
directors, or otherwise, in excess of the indemnification otherwise permitted by
Section 317 of the California Corporations Code, subject only to the applicable
limits set forth in Section 204 of the California Corporations Code with respect
to actions for breach of duty to the corporation and its shareholders.

         Dated: November 9, 1988

                                                /s/ Douglas B. Whiting
                                                ------------------------
                                                Douglas B. Whiting