Villano, Renato A., and Carolyn-Dung Thi Thanh Tran. “Technical Efficiency Heterogeneity of Tertiary Institutions in Viet Nam: A Metafrontier Directional Technology Approach”. Technological and Economic Development of Economy 25, no. 6 (September 17, 2019): 1058-1080. Accessed April 25, 2024. https://journals.vilniustech.lt/index.php/TEDE/article/view/7452.