S. Guha, R. Rastogi, und K. Shim. ICDE '99: Proceedings of the 15th International Conference on Data Engineering, Seite 512. Washington, DC, USA, IEEE Computer Society, (1999)
T. Zhang, R. Ramakrishnan, und M. Livny. SIGMOD '96: Proceedings of the 1996 ACM SIGMOD international conference on Management of data, Seite 103--114. New York, NY, USA, ACM, (1996)