Hartmut Ehrig, Horst Herrlich, Hans-Jörg Kreowski, Gerhard Preu , editors: Categorical Methods in Computer Science. Volume 393 of Lecture Notes in Computer Science. Springer, 1989.
Annegret Habel, Hans-Jörg Kreowski, Walter Vogler: Metatheorems for Decision Problems on Hyperedge Replacement Graph Languages. Acta Informatica 26:657-677, 1989.
Annegret Habel, Hans-Jörg Kreowski, Walter Vogler: Dedicable Boundedness Problems for Hyperedge Replacement Graph Grammars. In Proc. Joint Conference on Theory and Practice of Software Development TAPSOFT'89, Vol. 1, volume 351 of Lecture Notes in Computer Science, pages 275-289. Springer, 1989.
Hans-Jörg Kreowski: Colimits as Parametrerized Data Types. In Proc. Workshop on Categorial Methods in Computer Science - with Aspects from Topology, volume 393 of Lecture Notes in Computer Science, pages 36-49. Springer, 1989.
Hans-Jörg Kreowski: Informationstechnische Grundbildung für alle ist Unfug. In Felix Rauner, Julie K. Ruth, editors, Informationstechnische Grundbildung zwischen Affirmation und Gestaltungskompetenz, pages 27-38. Leuchtturm-Verlag, Alsbach, 1989.
