NIKOLAICHUK, A. M. Some estimations for partial indices of the Riemann boundary value problem . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 23, n. 6, p. 793–798, 1971. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8629. Acesso em: 14 apr. 2025.