@phdthesis{THESE_1934__163__1_0,
     author = {Tcheng Tchou-Yun},
     title = {Sur les in\'egalit\'es diff\'erentielles},
     series = {Th\`eses de l'entre-deux-guerres},
     number = {163},
     year = {1934},
     language = {fr},
     url = {http://www.numdam.org/item/THESE_1934__163__1_0/}
}