Graham-Witten’s Conformal Invariant for Closed Four Dimensional Submanifolds. Journal of Mathematical Study, [S. l.], v. 54, n. 2, p. 200–226, 2021. DOI: 10.4208/jms.v54n2.21.06. Disponível em: https://global-sci.com/index.php/jms/article/view/13394. Acesso em: 27 feb. 2026.