1. Fifth Annual Symposium on Logic in Computer Science (LICS’90), Philadelphia, June 1990. IEEE Computer Society Press
2. Abramsky S: Observation equivalence as a testing equivalence. Theor Comput Sci 53: 225–241 (1987)
3. Lect Notes Comput Sci;RJR Back,1989
4. Lect Notes Comput Sci;RJR Back,1989
5. Baeten JCM, Weijland WP: Process algebra. Cambridge Tracts in Theoretical Computer Science, vol 18. Cambridge University Press, Cambridge, England, 1990