D. Cutting, D. Karger, J. Pedersen, and J. Tukey. SIGIR '92: Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval, page 318--329. New York, NY, USA, ACM Press, (1992)
A. Bona, V. Zaccaria, and R. Zafalon. DATE '04: Proceedings of the Conference on Design, Automation and Test in Europe, page 30318. Washington, DC, USA, IEEE Computer Society, (2004)