On k -Generalized ψ -Hilfer Boundary Value Problems with Retardation and Anticipation. Advances in the Theory of Nonlinear Analysis and its Application, [S. l.], v. 6, n. 2, p. 173–190, 2023. Disponível em: https://atnaea.org/index.php/journal/article/view/124.. Acesso em: 2 apr. 2026.