@article{IM_1970__11_142044,
     author = {S. Smale},
     title = {Topology and {Mechanics.} {II.} {The} {Planar} {n-Body} {Problem.}},
     journal = {Inventiones mathematicae},
     pages = {45--64},
     publisher = {mathdoc},
     volume = {11},
     year = {1970},
     zbl = {0203.26102},
     url = {http://geodesic.mathdoc.fr/item/IM_1970__11_142044/}
}