Kifordu , A. Anthony, and Tina Ufuomanefe. “Determining Sales Growth through Effective Personal Marketing in the Telecommunication Industry”. Journal of Global Economics and Business 4, no. 14 (June 30, 2023): 95–117. Accessed April 4, 2025. https://journalsglobal.com/index.php/jgeb/article/view/177.