J. Pedro, and S. Siersdorfer. WWW '09: Proceedings of the 18th international conference on World wide web, page 771--780. New York, NY, USA, ACM, (2009)
G. Stumme. Proc. 3rd Intl. Conf. on Formal Concept Analysis, volume 3403 of Lecture Notes in Computer Science, page 315-328. Heidelberg, Springer, (2005)