A. Nurabadi, J. Irianto, I. Bafadal, J. Juharyanto, I. Gunawan, and M. A. Adha, “THE EFFECT OF INSTRUCTIONAL, TRANSFORMATIONAL AND SPIRITUAL LEADERSHIP ON ELEMENTARY SCHOOL TEACHERS’ PERFORMANCE AND STUDENTS’ ACHIEVEMENTS”, CP, vol. 40, no. 1, pp. 17–31, Feb. 2021.