Development skills of middle school principals in view of their performance. Journal Port Science Research, [S. l.], v. 2, n. 3, p. 413–437, 2019. DOI: 10.36371/port.2018.02.3.5. Disponível em: https://jpsr.uruk.edu.iq/index.php/jport/article/view/33. Acesso em: 13 may. 2026.