1. Auer, S., Bizer, C., Müller, C., Zhdanova, A.V. (eds.): The Social Semantic Web. LNI, vol. 113. Bonner Köllen Verlag (September 2007)
2. Bevan, N., Barnum, C., Cockton, G., Nielsen, J., Spool, J., Wixon, D.: The “magic number 5”: is it enough for web testing? In: CHI 2003: CHI 2003 extended abstracts on Human factors in computing systems, pp. 698–699. ACM Press, New York (2003)
3. Lecture Notes in Computer Science;J. Häkkilä,2005
4. Kaasinen, E.: User needs for location-aware mobile services. Int. J. of Personal and Ubiquitous Computing 7(1), 70–79 (2003)
5. Korpipää, P., Häkkilä, J., Malm, E.-J., Rantakokko, T., Kyllönen, V., Kela, J., Känsälä, I., Mäntyjärvi, J.: Customizing User Interaction in Smart Phones. IEEE Pervasive Computing: Mobile and Ubiquitous Systems 5(3), 82–90 (2006)