1. Sen, S., Joe-Wong, C., Ha, S., & Chiang, M. (2013). A survey of smart data pricing: Past proposals, current plans, and future trends. ACM Computing Surveys, 46(2), 15:1–15:37.
2. Varshney, U., Snow, A., McGivern, M., & Howard, C. (2002). Voice over IP. Communications of the ACM, 45(1), 89–96.
3. Clarke, R. N. (2012). The case for reforming regulation of PSTN voice services. Journal of Information Policy, 2, 287–313.
4. Verkasalo, H. (2006). Emerging trends in the Mobile VoIP business. In Seminar on networking business, Helsinki University of Technology.
5. Del Bianco, M. C. (2005). Voices past: The present and future of VoIP regulation. CommLaw Conspectus, 14, 365–401.