GOLO, S. Some remarks on contact variations in the first Heisenberg group. Annales Fennici Mathematici, [S. l.], v. 43, n. 1, p. 311–335, 2018. DOI: 10.5186/aasfm.2018.4312. Disponível em: https://afm.journal.fi/article/view/135726. Acesso em: 22 nov. 2024.