V. Shkapenyuk, and T. Suel. Proceedings of the 18th International Conference on Data Engineering (ICDE), San Jose, California, IEEE CS Press, (February 2002)
R. Baeza-Yates, and C. Castillo. Soft Computing Systems - Design, Management and Applications, page 565--572. Santiago, Chile, IOS Press Amsterdam, (2002)
D. Yazti, and M. Dikaiakos. Proceedings of the fifth Next Generation Information Technologies and Systems (NGITS), volume 2382 of Lecture Notes in Computer Science, page 58--74. Caesarea, Israel, Springer, (June 2002)