GONG, Guobin; JIAOTONG, Xi'an. 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://nnpub.org/index.php/MS/article/view/523.. Acesso em: 11 may. 2024.