Hartmut Ehrig. Algebraic Theory of Parameterized Specifications with Requirements. In Egidio Astesiano, Corrado Böhm, editors, CAAP 81, Trees in Algebra and Programming, 6th Colloquium, Genoa, Italy, March 5-7, 1981, Proceedings. Volume 112 of Lecture Notes in Computer Science, pages 1-24, Springer, 1981.
Abstract is missing.