GELBUKH, I. Reeb graphs of circle-valued functions: A survey and basic facts. Topological Methods in Nonlinear Analysis, [S. l.], v. 61, n. 1, p. 59–81, 2023. DOI: 10.12775/TMNA.2022.023. Disponível em: https://apcz.umk.pl/TMNA/article/view/42923. Acesso em: 3 jul. 2024.