1. R. Burstall, J. Goguen Putting theories together to make specifications. Proc. 5th Internat. Joint Conf. on Artificial Intelligence, Cambridge Mass., pp. 1045–1058, 1977.
2. R. Burstall, J. Goguen The semantics of CLEAR, a specification language. In: D. Bjorner (ed.): Proc. Advanced Course on Abstract Software Specifications. Lecture Notes in Computer Science. 86, Springer, Berlin, pp. 292–323, 1980.
3. M. Breu, M. Broy, T. Grünler, F. Nickl PAnndA-S Semantics Passau, 1989.
4. Th. Coquand, G. Huet The Calculus of Constructions. Information and Computation 76, pp. 95–120, 1988.
5. R. Dyckhoff Category Theory as an extension of Martin-Löf Type Theory. Department of Computational Science, University of St. Andrews, Techn. Report CS/85/3, 1985.