ROZENFELD, B. A.; EZHOVA-GUSEVA, L. M.; SEMENOVA, T. A. Metrical invariants and covariants of couples of planes in the flag space. Lithuanian Mathematical Journal, [S. l.], v. 4, n. 2, p. 255–259, 1964. DOI: 10.15388/LMJ.1964.19505. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19505.. Acesso em: 30 apr. 2024.