OKELO, N. B. NEW CONDITIONS FOR CONTRACTIVITY OF NORMALOID OPERATORS. Journal of Global Research in Mathematical Archives(JGRMA), [S. l.], v. 4, n. 9, p. 01–06, 2017. Disponível em: https://jgrma.com/index.php/jgrma/article/view/317. Acesso em: 14 mar. 2025.