Ratnaningtyas, Hapsari, et al. “Transformational Leadership and Work Motivation on Work Productivity Mediated by Work Engagement: An Introductory Analysis”. The International Journal of Social Sciences World (TIJOSSW), vol. 3, no. 2, July 2021, pp. 25-32, https://www.growingscholar.org/journal/index.php/TIJOSSW/article/view/129.