DOLECKI, S.; GRECO, G. H. Niveloids. Topological Methods in Nonlinear Analysis, [S. l.], v. 5, n. 1, p. 1–22, 1995. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1995.001. Acesso em: 3 jul. 2024.