A. Dickinger, A. Scharl, H. Stern, A. Weichselbraun, and K. Wöber. Information and Communication Technologies in Tourism 2008, Proceedings
of the International Conference in Innsbruck, Austria, 2008, Springer, Vienna-New York, (2008)
T. Rattenbury, N. Good, and M. Naaman. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 1287--1288. New York, NY, USA, ACM Press, (2007)