LANGAAS, T. Visual acuity in children: The development of crowded and single letter acuities. Scandinavian Journal of Optometry and Visual Science, [S. l.], v. 4, n. 2, p. 20–26, 2011. DOI: 10.5384/sjovs.vol4i2p21. Disponível em: https://sjovs.org/index.php/SJOVS/article/view/37. Acesso em: 6 jul. 2022.