HONKAPOHJA, M. Degree and point-inverses of mappings on spheres. Annales Fennici Mathematici, [S. l.], n. 447, 1969. DOI: 10.5186/aasfm.1969.447. Disponível em: https://afm.journal.fi/article/view/134123. Acesso em: 26 nov. 2024.