Kristiani, E., U. Sumarwan, L. N. Yuliati, and A. Saefuddin. “The Role of Relational Reward Benefits for Developing the Non-Financial Value of a Customer to an Organization: Structural Equation Modeling Approach”. Gadjah Mada International Journal of Business, Vol. 16, no. 2, Oct. 2014, pp. 111-42, https://dev.journal.ugm.ac.id/v3/gamaijb/article/view/15464.