SERGIENKO, I. V.; LYTVYN, O. N.; LYTVYN, O. O.; TKACHENKO, A. V.; GRITCAI, O. L. Interlineation of the functions of the three variables on a system of disjoint lines preserving the differentiability class . Reports of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, n. 1, p. 31–35, 2025. DOI: 10.15407/dopovidi2015.01.031. Disponível em: https://nasu-periodicals.org.ua/index.php/dp/article/view/12952. Acesso em: 10 jan. 2025.