1. Best, E.: A Theorem on the Characteristics of Non-Sequential Processes. TR/116, Computing Laboratory, University of Newcastle upon Tyne, November 1977. Also to appear in Fundamenta Informaticae.
2. Best, E.: Atomicity of Activities. In this volume.
3. Best, E.: Notes on Predicate Transformers and Concurrent Programs. TR/145, Computing Laboratory, University of Newcastle upon Tyne, 1979 (to appear).
4. Dijkstra, E.W.: A Discipline of Programming. Prentice Hall 1976.
5. Hewitt, C. and Baker, H.: Actors and Continuous Functionals. In: Formal Description of Programming Concepts (ed. E. Neuhold), North Holland 1978.