@article{701675,
     title = {On a class of polynomial Lagrangians},
     booktitle = {Proceedings of the 20th Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {2001},
     pages = {147-159},
     mrnumber = {MR1826688},
     zbl = {1002.58003},
     url = {http://dml.mathdoc.fr/item/701675}
}

Palese, Marcella; Vitolo, Raffaele. On a class of polynomial Lagrangians, dans Proceedings of the 20th Winter School "Geometry and Physics", GDML_Books,  (2001), pp. 147-159. http://gdmltest.u-ga.fr/item/701675/