MOLYBOGA, V. M.; MIKHAILETS, V. A. One-dimensional Schrödinger operators with singular periodic potentials. Methods of Functional Analysis and Topology, [S. l.], v. 14, n. 2, p. 184–200, 2008. Disponível em: https://zen.imath.kiev.ua/index.php/mfat/article/view/382. Acesso em: 17 dec. 2025.