1. W. G. Aref and H. Samet. Extending a DBMS with spatial operations. In O. Günther and H. J. Schek, editors, Advances in Spatial Databases — 2nd Symposium, SSD'91, pages 299–318, Berlin, 1991. Springer-Verlag. (also Lecture Notes in Computer Science 525).
2. W. G. Aref and H. Samet. Uniquely reporting spatial objects: yet another operation for comparing spatial data structures. In Proceedings of the Fifth International Symposium on Spatial Data Handling, pages 178–189, Charleston, South Carolina, August 1992.
3. S. Arya, D. M. Mount, N. S. Netanyahu, R. Silverman, and A. Wu. An optimal algorithm for approximate nearest neighbor searching. In Proceedings of the Fifth Annual ACM-SIAM Symposium on Discrete Algorithms, pages 573–582, Arlington, VA., January 1994.
4. D. Comer. The ubiquitous B-tree. ACM Computing Surveys, 11(2):121–137, June 1979.
5. L. M. Goldschlager. Short algorithms for space-filling curves. Software — Practice and Experience, 11(1):99, January 1981.