Development of knowledge in chemistry through elective courses at school. ILIM, [S. l.], v. 30, n. 4, p. 5–13, 2021. DOI: 10.47751/skspu-1937-0043. Disponível em: https://ilim.okmpu.kz/index.php/bulletin/article/view/85.. Acesso em: 13 nov. 2026.