KURBONOV, Gulomjon. ON THE NUMERICAL RANGE OF A 2x2 OPERATOR MATRIX. Journal of Global Research in Mathematical Archives(JGRMA), [S. l.], v. 6, n. 11, p. 52–54, 2019. Disponível em: https://jgrma.com/index.php/jgrma/article/view/567. Acesso em: 14 mar. 2025.