MASHADI, M.; DINATA, M. F. Double butterfly theorem on ellips. Hilbert Journal of Mathematical Analysis, [S. l.], v. 1, n. 1, p. 22–29, 2022. DOI: 10.62918/hjma.v1i1.6. Disponível em: https://hilbertjma.org/hilbertjma/article/view/6. Acesso em: 9 nov. 2024.