Razavyan, S. ., G. Tohidi, F. . Hosseinzadeh Lotfi, T. Allahviranloo, M. Shahriari, S. Samanta, and J.-G. Lee. “Uncertain Multi-Period Efficiency in Data Envelopment Analysis: Performance Evaluation of Healthcare Systems in the Face of COVID- 19 Pandemic”. Contemporary Mathematics, vol. 6, no. 4, Aug. 2025, pp. 5317-45, doi:10.37256/cm.6420257552.