Buehler, S. and Haucap, J. (2018). Mobile Number Portability. Journal of Industry, Competition and Trade, 4(3): 223-238.

Hashim, Y. M. (2014). Determinant of Customer Loyalty Among Subscribers of Global System for Mobile (GSM) Communication in North-Western Nigeria. The 2014 WEI International Academic Conference Proceeding New Orleans USA. 8:6-9.

Haucap, J. (2016). Endogenous Switching Costs and Exclusive Systems Applications. Review of Network Economics, 1, 29-35.

Igbal, T. (2017). Mobile Number Portability: The Case for and Against. LIRNE asia. Retrieved August 13, 2017 from: http://lirneasia.net/20017/10/mobilenumber-portability-the-case for-and-against/

Jibrin, N. S and Ahmad, A. (2014). Appraisal of Customer Satisfaction and GSM Services in

Dutsinma, Katsina State. European Journal of Business and Management, 6(35): 19-24

Lee, J., Kim, Y., and Park, Y. (2016). Estimating The Extent of Potential Competition in the Korean Mobile Telecommunications Market: Switching Costs and Number Portability’’, International Journal of Industrial Organization. Vol 6, No. 7. Pp 90-99.

Nilsson, G. (2017). Number Portability: A Networking Perspective.  Telecommunications Magazine, Retrieved July 24, 2017, from http://www.telecomsmag. com/marketing/articles/jul97/nilsson.html

Rajeev, R. K., Amrita, S., and Damodaram, A. (2018). Phone Number Portability in GSM Networks”, CSI Vol. 32, Issue-7,  Oct.2018.  Pp 34-39.

Smura, T. (2019). Mobile Number Portability. Case Finland, Mimeo, Networking Laboratory, Helsinki University of Technology. 78.