Takao Asano, Hiroshi Imai, D. T. Lee, Shin-Ichi Nakano, Takeshi Tokuyama: Computing and Combinatorics, 5th Annual International Conference, COCOON '99, Tokyo, Japan, July 26-28, 1999, Proceedings. Lecture Notes in Computer Science 1627, Springer 1999, ISBN 3-540-66200-6