Georg Gottlob, Roberto Zicari. Closed World Databases Opened Through Null Values. In François Bancilhon, David J. DeWitt, editors, Fourteenth International Conference on Very Large Data Bases, August 29 - September 1, 1988, Los Angeles, California, USA, Proceedings. pages 50-61, Morgan Kaufmann, 1988. [doi]
Abstract is missing.