BASUKI, S., P. PERDINANTO, and A. HAMID. “Effect of Strengthening Supervisory Training on Principal Competence”. Utopía Y Praxis Latinoamericana, Vol. 25, no. 1, Aug. 2020, pp. 353-64, http://www.produccioncientifica.luz.edu.ve/index.php/utopia/article/view/33543.