Hans-Joachim Klein. Null Values in Relational Databases and Sure Information Answers. In Leopoldo E. Bertossi, Gyula O. H. Katona, Klaus-Dieter Schewe, Bernhard Thalheim, editors, Semantics in Databases, Second International Workshop, Dagstuhl Castle, Germany, January 7-12, 2001, Revised Papers. Volume 2582 of Lecture Notes in Computer Science, pages 119-138, Springer, 2001. [doi]
Abstract is missing.