RABANOVYCH, V. I. On the Decomposition of an Operator into a Sum of Four Idempotents. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 56, n. 3, p. 419–424, 2004. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3764. Acesso em: 14 apr. 2025.