PIVOVARCHIK, V. N.; MARTYNYUK, O. M.; BOYKO, O. P. On a generalization of the three spectral inverse problem. Methods of Functional Analysis and Topology, [S. l.], v. 22, n. 1, p. 74–80, 2016. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/628. Acesso em: 16 dec. 2025.