@article{JMPA_1931_9_10__499_0,
     author = {JMPA},
     title = {Communication},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {499--499},
     publisher = {Gauthier-Villars},
     volume = {9e s{\'e}rie, 10},
     year = {1931},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1931_9_10__499_0/}
}