of the calculus of variations since the 1930s and initially it found very few applications in physics. Recently it was applied in theoretical physics in the context of quantum field theory and quantum gravity. In 1970, Jedrzej Śniatycki, the author of Geometric quantization and quantum mechanics, developed an invariant geometrical formulation of jet bundles, building on the work of De Donder and Weyl. In 1999 Igor Kanatchikov has shown that the De Donder–Weyl covariant Hamiltonian field equations can be formulated in terms of Duffin–Kemmer–Petiau matrices. See also Hamiltonian field theory Covariant Hamiltonian field theory Further reading Selected papers on GEODESIC FIELDS, Translated and edited by D. H. Delphenich. Part 1 , Part 2 H.A. Kastrup, Canonical theories of Lagrangian dynamical systems in physics, Physics Reports, Volume 101, Issues 1–2, Pages 1-167 (1983). Mark J. Gotay, James Isenberg, Jerrold E. Marsden, Richard Montgomery: "Momentum Maps and Classical Relativistic Fields. Part I: Covariant Field Theory" Cornelius Paufler, Hartmann Römer: De Donder–Weyl equations and multisymplectic geometry, Reports on Mathematical Physics, vol. 49 (2002), no. 2–3, pp. 325–334 Krzysztof Maurin: The Riemann legacy: Riemannian ideas in mathematics and physics, Part II, Chapter 7.16 Field theories for calculus of variation for multiple integrals, Kluwer Academic Publishers, , 1997, p. 482 ff. References Calculus of variations Mathematical physics