“Optimality and Duality for Nondifferentiable Multiobjective Variational Problems with Higher Order Derivatives”, Eur. J. Pure Appl. Math., vol. 2, no. 3, pp. 372–400, Aug. 2009, Accessed: Dec. 22, 2024. [Online]. Available: https://www.ejpam.com/index.php/ejpam/article/view/180