R. Firmansyah, D. M. Putri, M. G. S. Wicaksono, S. F. Putri, A. A. Widianto, and M. R. Palil, “Educational Transformation: An Evaluation of Online Learning Due To COVID-19”, Int. J. Emerg. Technol. Learn., vol. 16, no. 07, pp. pp. 61–76, Apr. 2021.