R. Jäschke, A. Hotho, C. Schmitz, and G. Stumme. Proceedings of the 15th International Conference on Conceptual Structures (ICCS 2007), volume 4604 of Lecture Notes in Artificial Intelligence, page 283--295. Berlin, Heidelberg, Springer-Verlag, (July 2007)
M. Heckner, T. Neubauer, and C. Wolff. SSM '08: Proceeding of the 2008 ACM workshop on Search in social media, page 3--10. New York, NY, USA, ACM, (2008)
O. Nov, M. Naaman, and C. Ye. CHI '08: Proceeding of the twenty-sixth annual SIGCHI conference on Human factors in computing systems, page 1097--1100. New York, NY, USA, ACM, (2008)
J. Leskovec, L. Backstrom, R. Kumar, and A. Tomkins. KDD '08: Proceeding of the 14th ACM SIGKDD international conference on Knowledge discovery and data mining, page 462--470. New York, NY, USA, ACM, (2008)