Breugelmans, Els, Tammo H A Bijmolt, Jie Zhang, Leonardo J Basso, Matilda Dorotic, Praveen Kopalle, Alec Minnema, Willem Jan Mijnlieff, and Nancy Wünderlich. “Advancing Research on Loyalty Programs: A Future Research Agenda.” Marketing Letters 26, no. 2 (2015): 127–39.