1. Goguen J., Thatcher J., Wagner E., "An Initial Algebra approach to the specification, correctness, and implementation of abstract data types" in Current Trends in Programming Methodology, Vol.4, Yeh Ed. Prentice Hall, 1978 (also IBM Report RC 6487, October 1976).
2. Gerhart S.L., "AFFIRM Reference Manual", UCS-Report (Marina del Rey), 1981.
3. Amar P., "Winnie: un éditeur de textes multifenêtres extensible", Actes des Journées BIGRE (Le Cap d'Agde), 1983.
4. Bidoit M., Biebow B., Gaudel M.-C., Gresse C., Guiho G., "Exception handling: formal specification and systematic program specification", Proc. 7th I.C.S.E., Orlando, USA, 1984.
5. Beaudouin-Lafon M., "Petripote: a graphic system for Petri-Nets design and simulation" Proc. of 4th European Workshop on Applications and Theory of Petri Nets, Toulouse, France, 1983.