A. Dambrauskas and V. Rinkevičius, “Algorithmic Methods of Variational Calculus”, ELEKTRON ELEKTROTECH, vol. 85, no. 5, pp. 25–28, May 2008, Accessed: Jan. 22, 2026. [Online]. Available: https://eejournal.ktu.lt/index.php/elt/article/view/11154