Determination of an exact solution to the integral Gelfand - Levitan - Marchenko equation for the Sturm - Liouville operators with the step-type potential. Neliniini Kolyvannya, [S. l.], v. 6, n. 1, p. 74–82, 2003. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/250. Acesso em: 22 jan. 2026.