@article{ASENS_2006_4_39_5_841_0,
     author = {Zung, Nguyen Tien},
     title = {Proper groupoids and momentum maps : linearization, affinity, and convexity},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {841--869},
     publisher = {Elsevier},
     volume = {Ser. 4, 39},
     number = {5},
     year = {2006},
     doi = {10.1016/j.ansens.2006.09.002},
     mrnumber = {2292634},
     zbl = {1163.22001},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/j.ansens.2006.09.002/}
}