Pratama, Ramadhan Chossy, et al. “Service Quality And Product Quality In Influence Ud Karomah Abadi Makmur Customer Loyalty”. Proceeding International Annual Conference Economics, Management, Business, and Accounting, vol. 1, no. 1, Feb. 2024, pp. 48-52, https://proceeding.inacemba.org/index.php/eproceeding-inacemba/article/view/7.