@techreport{BeierleBoettcherMeyer94,
   AUTHOR = "C. Beierle and S. B{\"{o}}ttcher and G. Meyer",
   TITLE = "{Report of the Logic Programming Language {PROTOS-L} 
             (revised version)}",
   TYPE = "Working Paper",
   NUMBER = "No 4",
   INSTITUTION = "IBM Germany, Scientific Center,
                  Inst. for Logics and Linguistics",
   ADDRESS = {Heidelberg},
   YEAR = 1994 , month = jul  }