AdlerS. L., Rev. Mod. Phys. 54, 729 (1982).
ArnoldV. I., Mathematical Methods of Classical Mechanics, Springer-Verlag, Berlin, Heidelberg, New York, 1978.
Boulware, D. G., In ahead of this time, in S. M. Christensen (ed.), B. S. De Witt: A Collection of Essays in Honour of his 60th Birthday, Bristol (1983).
BoulwareD. G. and DeserS., Phys. Rev. Lett. 55, 2656 (1984).
Ferraris, M., Francaviglia, M., and Magnano, G., Nonlinear gravitational Lagrangian, G.R.G., in print (1987).
FrancavigliaM. and KrupkaD. Ann. Inst. H. Poincaré 37, 295 (1982).
MoserJ., Comm. Pure Appl. Math. 11, 81 (1958).
MusickyD., J. Phys. A 11, 1 (1978).
NarnhoferH. and ThirringW., Phys. Lett. B 76, 428 (1978).
NekhoroshevN. N., Russian Math. Surveys 32, 1 (1978).
OstrogradskyM., Mem. Acad. St. Petersburg 6, 385 (1850).
PaisA. and UhlenbeckG. E., Phys. Rev. 79, 145 (1950).
Pagani, E., Tecchiolli, G., and Zerbini, S., Sulla stabita' dei sistemi lagrangiani di ordine superiore, Univ. Trento, unpublished report (1987).
PoincaréH., Les Méthodes nouvelles de la mécanique céleste, Guthier-Villars, Paris, 1982; Dover, New York, 1957.
SalvadoriL., Ann. Mat. Pura Appl. 69, 1 (1965).
SiegelC. L. and MoserJ. K., Lectures on Celestial Mechanics, Springer-Verlag, Berlin, Heidelberg, New York (1971).
StelleK. S., Phys. Rev. D16, 953 (1977).
Tecchiolli, G., Aspetti classici e quantistici di sistemi descritti da lagrangiane di ordine superiore nelle derivate, Tesi di Laurea in Fisica, Univ. di Trento (1986).
TkhaiV. N., P.M.M. U.S.S.R. 49, 273 (1985).
WhittakerE. T., A Treatise on the Analytical Dynamics of Particles and Rigid Bodies, Cambridge Univ. Press, Cambridge (1959).