GUPTA, M.; ACHARYA, L. R. Approximation numbers of matrix transformations and inclusion maps. Tamkang Journal of Mathematics, [S. l.], v. 42, n. 2, p. 193–203, 2011. DOI: 10.5556/j.tkjm.42.2011.924. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/924. Acesso em: 29 apr. 2024.