Suharto, Sugeng, K. Shankar, Phong Thanh Nguyen, Rustem A. Shichiyakh, y Endro Sukotjo. 2019. «Process Improvement of Business and Importance of Customer Feedback». Opción 35 (junio), 2899-2921. https://mail.produccioncientificaluz.org/index.php/opcion/article/view/30955.