I. Chatzigiannakis, O. Michail, and P. Spirakis. In: 34th International Symposium on Mathematical Foundations of Computer Science (MFCS, page 56--76. (2009)
J. Poelmans, P. Elzinga, S. Viaene, and G. Dedene. Proceedings of the 18th International Conference on Conceptual Structures (ICCS 2010), volume 6208 of Lecture Notes in Computer Science, page 139-153. Springer, (2010)
J. Poelmans, P. Elzinga, S. Viaene, and G. Dedene. Conceptual Structures: From Information to Intelligence, volume 6208 of Lecture Notes in Computer Science, Springer, Berlin/Heidelberg, (2010)
J. Poelmans, P. Elzinga, S. Viaene, and G. Dedene. Conceptual Structures: From Information to Intelligence, volume 6208 of Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, (2010)