@article{MAN_1992__292_2_164932,
     author = {Misha Bialy and Leonid Polterovich},
     title = {Hamiltonian systems, {Lagrangian} tori and {Birkhoffs's} theorem.},
     journal = {Mathematische Annalen},
     pages = {619--628},
     publisher = {mathdoc},
     volume = {292},
     number = {2},
     year = {1992},
     zbl = {0735.58016},
     url = {http://geodesic.mathdoc.fr/item/MAN_1992__292_2_164932/}
}