T. Do, and D. Gatica-Perez. Proceedings of the 9th International Conference on Mobile and Ubiquitous Multimedia (MUM '10), Limassol, Cyprus, page 27:1-27:10. ACM, (2010)
M. Böhmer, B. Hecht, J. Schöning, A. Krüger, and G. Bauer. Proceedings of MobileHCI '11: 13th International Conference on Human Computer Interaction with Mobile Devices and Services, Stockholm, Sweden, page 47-56. (2011)
T. Pederson, C. Ardito, P. Bottoni, and M. Costabile. Advances in Conceptual Modeling -- Challenges and Opportunities: ER 2008 Workshops CMLSA, ECDM, FP-UML, M2AS, RIGiM, SeCoGIS, WISM, Barcelona, Spain, volume 5232 of Lecture Notes in Computer Science, (2008)