F. Benevenuto, T. Rodrigues, M. Cha, and V. Almeida. Proceedings of the 9th ACM SIGCOMM Conference on Internet Measurement Conference, page 49--62. New York, NY, USA, ACM, (2009)
D. Abrams, R. Baecker, and M. Chignell. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 41--48. New York, NY, USA, ACM Press/Addison-Wesley Publishing Co., (1998)
S. Doerfel, R. Jäschke, and G. Stumme. ICFCA 2012, volume 7278 of Lecture Notes in Artificial Intelligence, page 77--95. Berlin/Heidelberg, Springer, (2012)
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)