@phdthesis{THESE_1927__75__1_0,
     author = {Delens, P.-C.},
     title = {M\'ethodes et probl\`emes des g\'eom\'etries diff\'erentielles euclidienne et conforme},
     series = {Th\`eses de l'entre-deux-guerres},
     number = {75},
     year = {1927},
     language = {fr},
     url = {http://www.numdam.org/item/THESE_1927__75__1_0/}
}