EXHIBIT A JOINT FILING AGREEMENT Jane Marvel Garnett and David G. Booth each hereby agree that the Schedule 13G filed herewith and any amendments thereto relating to the acquisition of shares of Common Stock of Southern Financial Bancorp., Inc. is...

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                                   EXHIBIT A

                             JOINT FILING AGREEMENT

          Xxxx Marvel Xxxxxxx and Xxxxx X. Xxxxx each hereby agree that the
Schedule 13G filed herewith and any amendments thereto relating to the
acquisition of shares of Common Stock of Southern Financial Bancorp., Inc. is 
filed jointly on behalf of each such person.


Dated: February 1, 1998


                                             /s/ Xxxx Marvel Xxxxxxx
                                             -----------------------------
                                              Xxxx Marvel Xxxxxxx


                                             /s/ Xxxxx X. Xxxxx
                                             -----------------------------
                                              Xxxxx X. Xxxxx