MOSKALEVA, Yu. P.; OSTROVSKYI, V. L.; YUSENKO, K. A. On quadruples of linearly connected projections and transitive systems of subspaces. Methods of Functional Analysis and Topology, [S. l.], v. 13, n. 1, p. 43–49, 2007. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/335. Acesso em: 16 dec. 2025.