MOLYBOGA, V. M.; MIKHAILETS, V. A. Spectral gaps of the Hill-Schrödinger operators with distributional potentials. Methods of Functional Analysis and Topology, [S. l.], v. 20, n. 4, p. 321–327, 2014. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/589. Acesso em: 16 dec. 2025.