L. Perusco and K. Michael, "Control, trust, privacy, and security: evaluating location-based services," in IEEE Technology and Society Magazine, vol. 26, no. 1, pp. 4-16, Spring 2007, doi: 10.1109/MTAS.2007.335564.

K. Michael, A. McNamee and M. Michael, "The Emerging Ethics of Humancentric GPS Tracking and Monitoring," 2006 International Conference on Mobile Business, Copenhagen, Denmark, 2006, pp. 34-34, doi: 10.1109/ICMB.2006.43.