Foundations of Fuzzy Logic and Soft Computing: 12th International Fuzzy Systems Association World Congress, IFSA 2007, Cancun, Mexico, June 18-21, 2007. Proceedings Gang Xiang, Vladik Kreinovich (auth.), Patricia Melin, Oscar Castillo, Luis T. Aguilar, Janusz Kacprzyk, Witold Pedrycz (eds.) 3540729178,9783540729174,9783540729501