Serum concentration of vitamin D and sociodemographic characteristics of an elderly population in northeast Brazil. Research, Society and Development, [S. l.], v. 10, n. 2, p. e5910212268, 2021. DOI: 10.33448/rsd-v10i2.12268. Disponível em: https://rsdjournal.org/rsd/article/view/12268. Acesso em: 5 dec. 2025.