F. Schmid. Proceedings of the 4. Internat. Symposium on Location Based Services & TeleCartography, 0, Department of Land Surveying & Geo-Informatics, HongKong Polytechnic University; HongKong, (2007)
M. Balzer, and O. Deussen. Proceedings of the Proceedings of the 2005 IEEE Symposium on Information Visualization, page 7--. Washington, DC, USA, IEEE Computer Society, (2005)