JOINT FILING AGREEMENT

                                                                      Exhibit A


                             JOINT FILING AGREEMENT


     The  undersigned,  and each of them,  do hereby  agree and  consent  to the
filing  of a single  statement  on  behalf  of all of them on  Schedule  13D and
amendments thereto, in accordance with the provisions of Rule 13d-1(k)(1) of the
Securities Exchange Act of 1934.

Dated:   April 27, 1998

                              By:       /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Name:  Xxxxxxxxx X. Xxxx, Xx.


                              By:       /s/ Xxxxx X. Xxxxxxx, Xx.
                                 -----------------------------------------------
                                   Name:  Xxxxx X. Xxxxxxx, Xx.


                              By:       /s/ Xxxxxx X. Xxxxxxxx
                                 -----------------------------------------------
                                   Name:  Xxxxxx X. Xxxxxxxx


                              By:       /s/ Xxxxx X. Xxxxxxx
                                 -----------------------------------------------
                                   Name:  Xxxxx X. Xxxxxxx


                              By:       /s/ V. Xxxxxx Xxxxxxxxxx, Xx.
                                 -----------------------------------------------
                                   Name:  V. Xxxxxx Xxxxxxxxxx, Xx.


                              By:       /s/ Xxxxxxx X. Xxxxxx
                                 -----------------------------------------------
                                   Name:  Xxxxxxx X. Xxxxxx


                              XXXXXXX MANAGEMENT COMPANY, L.P.


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   General Partner



                                     Page 38












                              XXXXXXX PARTNERS, L.P.

                              By:  Xxxxxxx Management Company, L.P.,
                                   General Partner


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   General Partner


                              XXXXXXX MANAGEMENT LIMITED, L.L.C.


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   Principal

                              XXXXXXX MANAGEMENT COMPANY II, L.P.

                              By:  Xxxxxxx Management Limited, L.L.C.,
                                   General Partner


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   Principal

                              XXXXXXX PARTNERS II, L.P.

                              By:  Xxxxxxx Management Company II, L.P.

                              By:  Xxxxxxx Management Limited, L.L.C.,
                                   General Partner


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   Principal

                              XXXXXXX AFFILIATES, L.P.


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   General Partner





                                     Page 39










                              XXXXXXX AFFILIATES II, L.P.


                              By:    /s/ Xxxxxxxxx X. Xxxx, Xx.
                                 -----------------------------------------------
                                   Xxxxxxxxx X. Xxxx, Xx.,
                                   General Partner



                                     Page 40