@article{BSMF_1957__85__1_0,
     author = {Papy, Georges},
     title = {Vari\'et\'es diff\'erentielles {(Point} de vue contingent)},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {1--14},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {85},
     year = {1957},
     doi = {10.24033/bsmf.1478},
     mrnumber = {20 #2027},
     zbl = {0103.15201},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/bsmf.1478/}
}