1. S. K. Pal and A. Skowron: “Rough Fuzzy Hybridization — A New Trend in Decision Making”, Springer Verlag, 1999.
2. A. Kanasugi: “Rough Processor”, Workshop on Rough sets — Foundations and Applications —, 2000.
3. A. Kanasugi and A. Yokoyama: “A Basic Design for Rough Set Processor”, Proc. of 15th JSAI Annual Conf, 1E1–02, 2001.