@article{AIHPB_1986__22_1_67_0,
     author = {Cattiaux, Patrick},
     title = {Hypoellipticit\'e et hypoellipticit\'e partielle pour les diffusions avec une condition fronti\`ere},
     journal = {Annales de l'I.H.P. Probabilit\'es et statistiques},
     pages = {67--112},
     publisher = {Gauthier-Villars},
     volume = {22},
     number = {1},
     year = {1986},
     mrnumber = {838373},
     zbl = {0595.60059},
     language = {fr},
     url = {http://www.numdam.org/item/AIHPB_1986__22_1_67_0/}
}