Theoretical Aspects of Computer Software International Conference TACS ’91, Sendai, Japan, September 24–27, 1991. Proceedings Ito Takayasu Heftet / 1991 / Engelsk
Logic at Botik '89 Symposium on Logical Foundations of Computer Science, Pereslavl-Zalessky, USSR, July 3-8, 1989, Proceedings Meyer Albert R. Heftet / 1989 / Engelsk
