Acatrinei, C., & Puiu, T. V. (2012). The Loyalty Card: Issues in Evaluating Loyalty Program Effectiveness. International Journal of Economic Practices and Theories, 2(3), 153-164. Retrieved from http://ijept.eu/index.php/ijept/article/view/The_Loyalty_Card%3A__Issues_in_Evaluating_Loyalty_Program_Effect