@article{CMJ_2009__59_3_a2,
     author = {Rainer, Armin},
     title = {Orbit projections of proper {Lie} groupoids as fibrations},
     journal = {Czechoslovak Mathematical Journal},
     pages = {591--594},
     publisher = {mathdoc},
     volume = {59},
     number = {3},
     year = {2009},
     mrnumber = {2545642},
     zbl = {1224.22005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_2009__59_3_a2/}
}