@article{GDZPPN002068613, title = {Estimates for the energy of a symplectic map.}, journal = {Commentarii mathematici Helvetici}, volume = {68}, year = {1993}, pages = {48-72}, zbl = {0787.58017}, url = {http://dml.mathdoc.fr/item/GDZPPN002068613} }
Hofer, H. Estimates for the energy of a symplectic map.. Commentarii mathematici Helvetici, Tome 68 (1993) pp. 48-72. http://gdmltest.u-ga.fr/item/GDZPPN002068613/