Georgieva, Bogdana, and Ronald B. Guenther. “Second Noether-Type Theorem for the Generalized Variational Principle of Herglotz”. Topological Methods in Nonlinear Analysis 26, no. 2 (December 1, 2005): 307–314. Accessed July 3, 2024. https://apcz.umk.pl/TMNA/article/view/TMNA.2005.034.