Freiburghouse, R. A. "The Multics PL/1 Compiler"

[AFIPS] (1969) [AFIPS] Proceedings of the 1969 Fall Joint Computer Conference FJCC 35  

Languages mentioned EPL {1966} Early PL/1 MULTICS PL/I {1968} Production PL/I compiler PL/I {1964} Programming Language One REPL {1966} Restricted EPL