**1**-
J.W. DE BAKKER, J.A. BERGSTRA, J.W. KLOP & J.-J.CH. MEYER (1984):
*Linear time and branching time semantics for recursion with merge.**Theoretical Computer Science*34, pp. 135-156. **2**-
B. BLOOM, S. ISTRAIL & A.R. MEYER (1988):
*Bisimulation can't be traced: Preliminary report.*In*Conference Record of the ACM Symposium on Principles of Programming Languages, San Diego, California*, pp. 229-239. Full version available as Technical Report 90-1150, Department of Computer Science, Cornell University, Ithaca, New York, August 1990. Accepted to appear in*Journal of the ACM*. **3**-
S.D. BROOKES, C.A.R. HOARE & A.W. ROSCOE (1984):
*A theory of communicating sequential processes.**Journal of the ACM*31(3), pp. 560-599. **4**-
P. DEGANO, R. DE NICOLA & U. MONTANARI (1989):
*Partial orderings descriptions and observations of nondeterministic concurrent processes.*In J.W. de Bakker, W.P. de Roever & G. Rozenberg, editors:*REX School/Workshop on Linear Time, Branching Time and Partial Order in Logics and Models for Concurrency, Noordwijkerhout*, **5**-
R. DE NICOLA, U. MONTANARI & F.W. VAANDRAGER (1990):
*Back and forth bisimulations.*In J.C.M. Baeten & J.W. Klop, editors:*Proceedings CONCUR 90, Amsterdam*, **6**-
R.J. VAN GLABBEEK (1993):
*The linear time - branching time spectrum II; the semantics of sequential systems with silent moves.*Preliminary version available from`boole.stanford.edu`. Extended abstract to appear in*Proceedings CONCUR 93*, Hildesheim, Germany, LNCS, Springer-Verlag. **7**-
R.J. VAN GLABBEEK & W.P. WEIJLAND (1989):
*Branching time and abstraction in bisimulation semantics (extended abstract).*In G.X. Ritter, editor:*Information Processing 89*, North-Holland, pp. 613-618. Full version available as Report CS-R9120, CWI, Amsterdam, 1991. **8**-
R. MILNER (1990):
*Operational and algebraic semantics of concurrent processes.*In J. van Leeuwen, editor:*Handbook of Theoretical Computer Science*, chapter 19, Elsevier Science Publishers B.V. (North-Holland), pp. 1201-1242. Alternatively see*Communication and Concurrency*, Prentice-Hall International, Englewood Cliffs, 1989, of which an earlier version appeared as*A Calculus of Communicating Systems*, LNCS 92, Springer-Verlag, 1980. **9**-
A. PNUELI (1985):
*Linear and branching structures in the semantics and logics of reactive systems.*In W. Brauer, editor:*Proceedings ICALP, Nafplion*,