Sudung Simatupang, Marto Silalahi, Kevin Indajang, and Injen Pardamean Butarbutar. “Employee Performance Influenced by Transformational Leadership and Work Spirit”. Journal of Innovation in Education and Social Research 1, no. 1 (June 1, 2023): 1–14. Accessed April 4, 2026. https://journals.proindex.uz/index.php/JIESR/article/view/1.