GRINCEVIČIUS, K. Differentilalumgebung dritter Ordnung des Strahlenkomplexs. Lithuanian Mathematical Journal, [S. l.], v. 1, n. 1-2, p. 87–97, 1961. DOI: 10.15388/LMJ.1961.19205. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19205.. Acesso em: 20 jul. 2024.