Antoni Kreczmar Grazyna Mirkowska Mathematical Foundations of Computer Science 1989, MFCS'89, Porabka-Kozubnik, Poland, August 28 - September 1, 1989, Proceedings MFCS Lecture Notes in Computer Science 379 Springer 1989 3-540-51486-4 db/conf/mfcs/mfcs89.html