@phdthesis{THESE_1919__15__1_0,
     author = {Egnell, Axel},
     title = {G\'eom\'etrie infinit\'esimale vectorielle},
     series = {Th\`eses de l'entre-deux-guerres},
     number = {15},
     year = {1919},
     language = {fr},
     url = {http://www.numdam.org/item/THESE_1919__15__1_0/}
}