@article{CMH_1981__56_139883,
     author = {Richard McGehee},
     title = {Double collisions for a classical particle system with nongravitational interactions.},
     journal = {Commentarii mathematici Helvetici},
     pages = {524--557},
     publisher = {mathdoc},
     volume = {56},
     year = {1981},
     zbl = {0498.70015},
     url = {http://geodesic.mathdoc.fr/item/CMH_1981__56_139883/}
}