Canonical formulation of newtonian dynamics J. Śniatycki, W. M. Tulczyjew (1972) Annales de l'I.H.P. Physique théorique
Comment by the editors on the paper : “The hamiltonian formalism in higher order variational problems” M. Francaviglia, D. Krupka (1985) Annales de l'I.H.P. Physique théorique
Critical Point Theorems for Indefinite Functionals. Vieri Benci, Paul H. Rabinowitz (1979) Inventiones mathematicae