Robin Milner. A Modal Characterisation of Observable Machine-Behaviour. In Egidio Astesiano, Corrado Böhm, editors, CAAP 81, Trees in Algebra and Programming, 6th Colloquium, Genoa, Italy, March 5-7, 1981, Proceedings. Volume 112 of Lecture Notes in Computer Science, pages 25-34, Springer, 1981.
Abstract is missing.