Hadzieva, E., J. Guncaga, S. C. Bose, and K. S. Ivanoska. “Introductory Survey on Challenges Encountered by University Teachers in Online Teaching of STEM Subjects During COVID-19 Lockdown”. Central European Journal of Educational Research, vol. 3, no. 3, Nov. 2021, pp. 22-32, doi:10.37441/cejer/2021/3/3/9601.