Kim Bruce, et al "Safe and Decidable Type Checking in an Object Oriented Language" in "Object-Oriented Programming, Systems, and Applications (OOPSLA)" Washington 1993

[OOPSLA 1993] (1993) [ACM SIGPLAN] SIGPLAN Notices 28(10) October 1993 Proceedings of the Conference on Object Oriented Programming Systems, Languages and Applications, Sept-Oct 1993. (OOPSLA '93)  

Languages mentioned TOOPLE {1993}