RAFFANIA ARSYILA DISYAH; NABILA ZAHRA SYAELI; RAZI DAHLAN; MUHAMMAD NABIL AKBAR; RISNA MIRA BELLA SARAGIH. THE EFFECT OF SLEEP PATTERNS ON LEARNING CONCENTRATION OF GRADE XII STUDENTS OF AL AZHAR MEDAN OUTSTANDING HIGH SCHOOL. Bulletin of Engineering Science, Technology and Industry, [S. l.], v. 4, n. 4, p. 2243–2250, 2026. Disponível em: https://bestijournal.org/index.php/go/article/view/263. Acesso em: 18 oct. 2026.