THE IMPACT OF VITAMIN B12 DEFICIENCY ON LEARNING PERFORMANCE AND NERVOUS SYSTEM FUNCTION IN SCHOOL-AGED CHILDREN. International Congress on Economics, Management and Business Studies, [S. l.], v. 1, n. 3, p. 148–152, 2026. Disponível em: https://www.econferencia.com/index.php/8/article/view/358. Acesso em: 13 may. 2026.