Elshafei, A. (1969). General Purpose Systems Simulator (GPSS). The Institute of National Planning.
Chicago-referens (17:e uppl.)Elshafei, Alwalid. General Purpose Systems Simulator (GPSS). Cairo: The Institute of National Planning, 1969.
MLA-referens (9:e uppl.)Elshafei, Alwalid. General Purpose Systems Simulator (GPSS). The Institute of National Planning, 1969.