@article{MZ_1990__205_3_174191,
     author = {Richard Moeckel},
     title = {On central configurations.},
     journal = {Mathematische Zeitschrift},
     pages = {499--518},
     year = {1990},
     volume = {205},
     number = {3},
     zbl = {0684.70005},
     url = {http://geodesic.mathdoc.fr/item/MZ_1990__205_3_174191/}
}