1. A general axiomatizability theorem formulated in terms of cone-injective;Andréka,1981
2. Constraints and their Normal Forms in the Framework of Specification Logics;Baldamus,1990
3. Unifying initial and loose semantics of parameterized specifications in an arbitary institutions;Baumeister,1991
4. Fibred categories and the foundations of naive category theorem;Benabou;J. Symbolic Logic,1985
5. Algebraic specification of modules and their basic interconnections;Blum;J. Comput. System Sci.,1987