@article{1104270713, author = {Gallavotti, Giovanni}, title = {Twistless KAM tori}, journal = {Comm. Math. Phys.}, volume = {159}, number = {1}, year = {1994}, pages = { 145-156}, language = {en}, url = {http://dml.mathdoc.fr/item/1104270713} }
Gallavotti, Giovanni. Twistless KAM tori. Comm. Math. Phys., Tome 159 (1994) no. 1, pp. 145-156. http://gdmltest.u-ga.fr/item/1104270713/