SAMOILENKO, Yu. S.; STRILETS, O. V. On simple $n$-tuples of subspaces of a Hilbert space. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 61, n. 12, p. 1668–1703, 2009. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3130. Acesso em: 5 dec. 2025.