@article{JMPA_1934_9_13__19_0,
     author = {Delsarte, J.},
     title = {Sur les $ds^2$ binaires et le probl\`eme {d'Einstein}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {19--67},
     publisher = {Gauthier-Villars},
     volume = {9e s{\'e}rie, 13},
     year = {1934},
     zbl = {0008.41702},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1934_9_13__19_0/}
}