CHAN, C. F. A REMARK ON BOUNDEDNESS OF THE NUMERICAL RANGE. Tamkang Journal of Mathematics, [S. l.], v. 22, n. 3, p. 271–273, 1991. DOI: 10.5556/j.tkjm.22.1991.4611. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4611. Acesso em: 25 apr. 2024.