P. Kiefer, S. Matyas, and C. Schlieder. Advances in Computer Entertainment Technology, volume 203 of ACM International Conference Proceeding Series, page 250-251. ACM, (2007)
K. Stein, R. Wegener, and C. Schlieder. The Influence of Technology on Social Network Analysis and Mining, volume 6 of Lecture Notes in Social Networks, Springer Vienna, (2013)