Yaron Kanza, Werner Nutt, Yehoshua Sagiv. Queries with Incomplete Answers over Semistructured Data. In Proceedings of the Eighteenth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, May 31 - June 2, 1999, Philadelphia, Pennsylvania. pages 227-236, ACM Press, 1999. [doi]
Abstract is missing.