BAU, Sheng. Graphs, contraction mappings and minors. Journal of Institute of Mathematics and Digital Technology, [S. l.], v. 6, n. 1, p. 1–13, 2024. DOI: 10.5564/jimdt.v6i1.3606. Disponível em: https://mongoliajol.info/index.php/JIMDT/article/view/3606. Acesso em: 5 dec. 2025.