ŠILERIS, V. Die Lösung einer elliptischen Gleichungsystem. Lithuanian Mathematical Journal, [S. l.], v. 7, n. 1, p. 157–165, 1967. DOI: 10.15388/LMJ.1967.19941. Disponível em: https://www.journals.vu.lt/LMJ/article/view/19941.. Acesso em: 3 may. 2024.