Z. Yu, X. Zhou, и Y. Nakamura. Ubiquitous Intelligence and Computing, том 5061 из Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2008)
G. Mineau. Proceedings of the 10th International Conference on Conceptual Structures (ICCS 2002), том 2393 из Lecture Notes in Computer Science, стр. 250-260. Springer, (2002)