Razavyan, Shabnam, Ghasem Tohidi, Farhad Hosseinzadeh Lotfi, Tofigh Allahviranloo, Mohammadreza Shahriari, Sovan Samanta, and Jeong-Gon Lee. “Uncertain Multi-Period Efficiency in Data Envelopment Analysis: Performance Evaluation of Healthcare Systems in the Face of COVID- 19 Pandemic”. Contemporary Mathematics 6, no. 4 (August 25, 2025): 5317–5345. Accessed January 10, 2026. https://ojs.wiserpub.com/index.php/CM/article/view/7552.