@article{10_4153_CJM_2001_029_1,
     author = {Cushman, Richard and \'Sniatycki, J\k{e}drzej},
     title = {Differential {Structure} of {Orbit} {Spaces}},
     journal = {Canadian journal of mathematics},
     pages = {715--755},
     year = {2001},
     volume = {53},
     number = {4},
     doi = {10.4153/CJM-2001-029-1},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2001-029-1/}
}