Jan Paredaens, Jan Van den Bussche, Dirk Van Gucht. Towards a Theory of Spatial Database Queries. In Proceedings of the Thirteenth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, May 24-26, 1994, Minneapolis, Minnesota. pages 279-288, ACM Press, 1994. [doi]
Abstract is missing.