SYMMETRY GROUPS AND INTEGRATING FACTORS OF TOTAL DIFFERENTIAL EQUATIONS IN THREE VARIABLES. Far East Journal of Applied Mathematics, [S. l.], v. 116, n. 4, p. 377–391, 2023. DOI: 10.17654/0972096023018. Disponível em: https://pphmjopenaccess.com/fejam/article/view/1252. Acesso em: 5 jan. 2026.