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• [1] Fatibene, L., Francaviglia, M., Natural and Gauge Natural Formalism for Classical Field Theories, Kluver, 2003.
• [2] Kolar, I., Michor, P.W., Slovak, J., Natural Operations in Di®erential Geometry, Springer Verlag, 1993.
• [3] Kolar, I., Modugno, M., Torsions of connectionons on some natural bundles, Differential Geom. Appl., 2(1992), 1-16.
• [4] Kurek, J., Mikulski, W.M., The natural a±nors on the r-th order frame bundle, Demonstratio Math. 41(3)(2008), to appear.
• [5] Kurek, J., Mikulski, W.M., Canonical vector valued 1-forms on higher order principal pro- longations, Lobachevskii Math. J., (2008), to appear.
• [6] de Leon, M., Rodrigues, P.R., Generalized Classical Mechanics and Field Theory, North- Holland Math. Studies 112, 1985, Amsterdam.
• [7] Palais, R., The Geometrization of Physics, Lecture Notes in Mathematics, Taiwan, 1981.