Lagrangian formalism in the classical field theory Wiktor Szczyrba (1976) Annales Polonici Mathematici
Le formalisme de Hamilton-Cartan en calcul des variations Hubert Goldschmidt (1973) Recherche Coopérative sur Programme n°25
Linear optimal control system with incomplete information about state of system Miloš Fink, Jan Štecha (1971) Kybernetika