Giorgio Ghelli. A Class Abstraction for a Hierarchical Type System. In Serge Abiteboul, Paris C. Kanellakis, editors, ICDT 90, Third International Conference on Database Theory, Paris, France, December 12-14, 1990, Proceedings. Volume 470 of Lecture Notes in Computer Science, pages 56-71, Springer, 1990. [doi]
Abstract is missing.