Purba, S., B. Ambarita, and P. Siburian. “The Academic Supervision Model-Based Education Management in Improving Teacher Performance”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 25, no. 2, Jan. 2016, pp. 36-43, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/5100.