Omar, M. A., M. S. A. Majid, and R. Rulindo. “Efficiency and Productivity Performance of the National Private Banks in Indonesia”. Gadjah Mada International Journal of Business, Vol. 9, no. 1, Jan. 2007, pp. 1-18, https://journal.ugm.ac.id/v3/gamaijb/article/view/14915.