OSILENKER, B. P. M. G. Krein’s ideas in the theory of orthogonal polynomials. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 1-2, p. 76–86, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5771. Acesso em: 6 dec. 2025.