1. W3C. (2002). P3P preference exchange language 1.0 (APPEL). Retrieved July 5, 2013, from http://www.w3.org/TR/P3P-preferences/
2. W3C. (2003). Enterprise privacy authorization language (EPAL 1.2). Retrieved July 5, 2013, from http://www.w3.org/Submission/2003/SUBM-EPAL-20031110/
3. W3C. (2004). Web services architecture requirements. Retrieved July 5, 2013, from http://www.w3.org/TR/wsa-reqs/
4. W3C. (2006). The platform for privacy preferences 1.1 (P3P1.1) specification. Retrieved July 5, 2013, from http://www.w3.org/TR/P3P11/
5. Abowd, G. D., Dey, A. K., Brown, P. J., Davies, N., Smith, M., & Steggles, P. (1999). Towards a better understanding of context and context-awareness. In Proceedings of the 1st international symposium on Handheld and Ubiquitous Computing, Karlsruhe, Germany (pp. 304-307).