A. P. S. C. Almeida, B. P. Nunes, S. M. S. Duro, and L. A. Facchini, “Socioeconomic determinants of access to health services among older adults: a systematic review”, Rev. saúde pública, vol. 51, p. 50, Jan. 2017, doi: 10.1590/s1518-8787.2017051006661.