1. Backhouse, J., et al., ‘A question of trust: An economic perspective on quality standards in the certification services market’, Communications of the ACM, Vol. 48, No. 9, ACM Press, Wash. DC, 2005, pp. 87–91.
2. Barkhuus, L. and Dey, A. ‘Location Based Services for Mobile Telephony: a study of users’ privacy concerns’, Interact, Zurich, 2003.
3. Chaum, D. ‘Untraceable electronic mail, return addresses, and digital pseudonyms’, Communications of the ACM, Vol. 4, No. 2, Wash. DC, 1981.
4. Clarke, R., ‘Profiling: A Hidden Challenge to the Regulation of Data Surveillance’, Journal of Law and Information Science, Vol. 4, No. 2, 1993.
5. Clarke R., ‘The Digital Persona and its application to Data Surveillance’, The Information Society, Vol. 10, No. 2, Taylor and Francis, 1994, pp. 77–92.