M. de Sá, and L. Carriço. MobileHCI '09 Proceedings of the 11th International Conference on Human-Computer Interaction with Mobile Devices and Services, ACM Press, (2009)
A. Geven, R. Sefelin, and M. Tscheligi. Proceedings of the 8th conference on Human-computer interaction with mobile devices and services, page 164. (2006)
H. Kim, J. Kim, Y. Lee, M. Chae, and Y. Choi. PROCEEDINGS OF THE 35 TH ANNUAL HAWAII INTERNATIONAL CONFERENCE ON SYSTEM SCIENCES, LOS ALAMITOS, CA: IEEE COMPUTER, (2002)