ZAGORODNYUK, Sergey M. A refined polar decomposition for $\boldsymbol{J}$-unitary operators. Sarajevo Journal of Mathematics, [S. l.], v. 11, n. 1, p. 65–72, 2015. DOI: 10.5644/SJM.11.1.05. Disponível em: https://sjm.anubih.ba/index.php/sjm/article/view/537. Acesso em: 25 dec. 2025.