A. Fatahi, R. Yousefian Molla, and M. Ameli, “Maintenance of Physical Fitness Levels in Junior Volleyball Players during COVID-19 with Protective Measures against the Pandemic Condition: Maintenance of physical fitness in volleyball players during COVID-19”, J Clin Physiother Res, vol. 6, no. 1, p. e27, Jan. 2021.