GONG, Guobin; XIA, Jun. A REVISIT TO HIGHER VARIATIONS OF A FUNCTIONAL. Journal of Advance Research in Mathematics And Statistics (ISSN 2208-2409), [S. l.], v. 6, n. 2, p. 01–09, 2019. DOI: 10.53555/nnms.v6i2.523. Disponível em: https://jarm-s.com/index.php/MS/article/view/26.. Acesso em: 14 jun. 2025.