“The Effectual Use of Customer Retention As a Tool of Customer Relations Management Strategy: A Study of Mtn, Airtel, Glo And Etisalat Communication Customers in UYO Metropolis”. 2019. Global Journal of Management and Business Research 19 (B2): 41-76. https://journalofbusiness.org/index.php/GJMBR/article/view/2766.