ENGLISH 1 EFFECT OF HEAD TEACHER’S PROFESSIONAL SKILLS ON THE PERFORMANCE OF SECONDARY SCHOOL TEACHERS AND STUDENTS. The International Research Journal of Usooluddin , [S. l.], v. 4, n. 2, p. 1–14, 2020. Disponível em: https://www.journalusooluddin.com/index.php/irjdu/article/view/103. Acesso em: 13 aug. 2026.