@article{JMPA_1937_9_16_1-4_315_0,
     author = {Vincensini, Paul},
     title = {Sur la courbure des congruences de sph\`eres et les congruences de courbure constante},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {315--328},
     publisher = {Gauthier-Villars},
     volume = {9e s{\'e}rie, 16},
     number = {1-4},
     year = {1937},
     zbl = {0018.08801},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1937_9_16_1-4_315_0/}
}