Usman H. Principals’ Effective Task Performance: A Tool for Proper Education Delivery in Nigerian Secondary Schools. JIESS [Internet]. 2020 Nov. 1 [cited 2026 May 28];1(2):74-8. Available from: https://training-ojs3-publikasi.mercubuana.ac.id/index.php/jiess/article/view/jiess.2020.v1i2.003