Bertrand Meyer. A Three-Level Approach to the Description of Data Structures, and Notational Framework. In Michael L. Brodie, Stephen N. Zilles, editors, Proceedings of the Workshop on Data Abstraction, Databases and Conceptual Modelling, Pingree Park, Colorado, June 23-26, 1980. Volume 11 of pages 164-166, ACM Press, 1980. [doi]