Hartmut Ehrig, Hans-Jörg Kreowski: A Graph Grammar Approach to Optimal and Consistent Schedules in Data Base Systems. In Uwe Pape, editor, Proc. Workshop WG'79 Graphentheoretische Konzepte in der Informatik (Berlin 1979, Discrete Structures and Algorithms, pages 223-240. Hanser, 1980.
Hartmut Ehrig, Hans-Jörg Kreowski, Peter Padawitz: Algebraic Implementation of Abstract Data Types: Concept, Syntax, Semantics and Correctness. In Proc. International Conference on Automata, Languages and Programming (Noordwijkerhout, July 1980), volume 85 of Lecture Notes in Computer Science, pages 142-156. Springer, 1980.
Hartmut Ehrig, Hans-Jörg Kreowski, Bernd Mahr, Peter Padawitz: Compound Algebraic Implementations: An Approach to Stepwise Refinement of Software Systems. In Proc. Conference Math. Foundations of Computer Science (Rydzyna, Sept. 1980), volume 88 of Lecture Notes in Computer Science, pages 231-245. Springer, 1980.
Hartmut Ehrig, Hans-Jörg Kreowski, Peter Padawitz: A Case Study of Abstract Implementations and Their Correctness. In Proc. Symposium on Programming (Paris, April 1980), volume 83 of Lecture Notes in Computer Science, pages 108-122. Springer, 1980.
Hartmut Ehrig, Hans-Jörg Kreowski, James W. Thatcher, Eric Wagner, Jesse Wright: Parameterized Data Types in Algebraic Specification Languages. In Proc. International Conference on Automata, Languages and Programming (Noordwijkerhout, July 1980), volume 85 of Lecture Notes in Computer Science, pages 157-168. Springer, 1980.
Hartmut Ehrig, Hans-Jörg Kreowski: Applications of Graph Grammar Theory to Consistency, Synchronization and Scheduling in Data Base Systems. Information Systems 5:225-238, 1980.
