Sohrabi, B., M. Haghighi, and A. Khanlari. “Customer Relationship Management Maturity Model (CRM3): A Model for Stepwise Implementation”. Journal of Human Sciences, vol. 7, no. 1, Jan. 2010, pp. 1-20, https://www.j-humansciences.com/ojs/index.php/IJHS/article/view/802.