V. Giarratana, F. Gimona, Ugo Montanari. Observability Concepts in Abstract Data Type Specifications. In Antoni W. Mazurkiewicz, editor, Mathematical Foundations of Computer Science 1976, 5th Symposium, Gdansk, Poland, September 6-10, 1976, Proceedings. Volume 45 of Lecture Notes in Computer Science, pages 576-587, Springer, 1976.
Abstract is missing.