MELIK-ADAMYAN, Perch. On the Canonical Calkin Reduction Operator. Armenian Journal of Mathematics, Yerevan, Armenia, v. 6, n. 1, p. 16–31, 2014. Disponível em: https://armjmath.sci.am/index.php/ajm/article/view/98. Acesso em: 4 apr. 2025.