ROZENFELD, B. A.; KARPOVA, L. M.; ANDREEVA, L. P. Metrical invariants and covariants of couples of planes in the quasielliptic space. Lithuanian Mathematical Journal, [S. l.], v. 4, n. 2, p. 241–253, 1964. DOI: 10.15388/LMJ.1964.19504. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19504. Acesso em: 14 apr. 2025.