Rinawati, L., R. Harno, and P. S. N. Hasibuan. “OPTIMIZATION OF CUSTOMER LOYALTY AT COFFEE SHOPS IN SURABAYA”. JOURNAL OF HUMANITIES, SOCIAL SCIENCES AND BUSINESS, vol. 2, no. 3, Apr. 2023, pp. 392-03, doi:10.55047/jhssb.v2i3.584.