Paepcke, A. "PCLOS: a critical review" pp221-253

[SIGPLAN] (1989) SIGPLAN Notices 24(10) October 1989 incorporating the Proceedings of the Conference on Object Oriented Programming Systems Languages and Applications, New Orleans (OOPSLA 89)  

Languages mentioned PCLOS {1993} Persistent CLOS PS-ALGOL {1981} Persistent Algol