Necessary and Sufficient conditions for Existence of Solutions of a Divergence-type Variational Problem. São Paulo Journal of Mathematical Sciences, [S. l.], v. 2, n. 2, p. 309–324, 2008. DOI: 10.11606/issn.2316-9028.v2i2p309-324. Disponível em: https://periodicos.usp.br/spjournal/article/view/33.. Acesso em: 17 abr. 2025.