1. Abadi, M., Lamport, L.: Composing Specifications. Digital Systems Research Center, SRC Report 66 (October 1990)
2. Breitling, M., Philipps, J.: Black Box View of State Machines. TUM-19916, SFB-Bericht Nr. 34L/07/99A, Institut für Informatik, Technische Universität München (1999)
3. Broy, M.: Compositional Refinement of Interactive Systems. In: DIGITAL Systems Research Center, SRC 89 (1992);
4. Also in: Journal of the ACM 44(6), 850-891 (November 1997)
5. Broy, M.: The Specification of System Components by State Transition Diagrams. Technische Universität München, Institut für Informatik, TUM-I9729, Mai (1997 )