BLIZNIKAS, V. Zur Krümmungstheorie im Stützelementenraum. Lithuanian Mathematical Journal, [S. l.], v. 5, n. 1, p. 9–24, 1965. DOI: 10.15388/LMJ.1965.19538. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19538.. Acesso em: 8 may. 2024.