TELAUMBANUA, F. .; SILALAHI, H. R. .; SIMANJUNTAK, J. .; SIREGAR, S. R. .; SIMANGUNSONG, M. I. .; PANJAITAN, S. .; HUTAURUK, A. J. . Psychological Encouragement for High School Students in Preparation for Online Learning During Covid-19. Middle European Scientific Bulletin, v. 14, 21 Jul. 2021.