Donald Sannella, Andrzej Tarlecki. Observability Concepts in Abstract Data Type Specification, 30 Years Later. In Pierpaolo Degano, Rocco De Nicola, José Meseguer, editors, Concurrency, Graphs and Models, Essays Dedicated to Ugo Montanari on the Occasion of His 65th Birthday. Volume 5065 of Lecture Notes in Computer Science, pages 593-617, Springer, 2008. [doi]
Abstract is missing.