@article{IM_1985__81_143251,
     author = {H. Hofer and I. Ekeland},
     title = {Periodic solutions with prescribed minimal period for convex autonomous hamiltonian systems.},
     journal = {Inventiones mathematicae},
     pages = {155--188},
     publisher = {mathdoc},
     volume = {81},
     year = {1985},
     zbl = {0594.58035},
     url = {http://geodesic.mathdoc.fr/item/IM_1985__81_143251/}
}