Akbar, M. A., Y. A. Soomro, and S. Khan. “Analytical Study of Reducing Brand Switching (Number Portablity) In GSM Sector”. JISR Management and Social Sciences & Economics, vol. 15, no. 2, Dec. 2017, pp. 31-46, doi:10.31384/jisrmsse/2017.15.2.3.