FELDMAN, G.; MURAZ, G. On an isometric representation with the maximal set of spectral subspaces. Математическая физика, анализ, геометрия, Харків, Україна, v. 5, n. 3-4, p. 297–303, 1998. Disponível em: https://mag.ilt.kharkiv.ua/index.php/mag/article/view/m05-0297e. Acesso em: 21 лис. 2024.