[1]
C. N. Wang and X. T. Nguyen, “A Hybrid Approach for Measuring Productivity in the Global Fitness Industry by Using Grey and DEA Model”, ASRJETS-Journal, vol. 38, no. 1, pp. 33–47, Nov. 2017, Accessed: Mar. 16, 2026. [Online]. Available: https://www.asrjetsjournal.org/American_Scientific_Journal/article/view/3591