IGNATIEV, M. Inverse scattering problem for Sturm-Liouville operator on one-vertex noncompact graph with a cycle. Tamkang Journal of Mathematics, [S. l.], v. 42, n. 3, p. 365–384, 2011. DOI: 10.5556/j.tkjm.42.2011.913. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/913. Acesso em: 3 may. 2024.