@book{MSM_1927__25__1_0,
     author = {Darmois, Georges},
     title = {Les \'equations de la gravitation einsteinienne},
     series = {M\'emorial des sciences math\'ematiques},
     publisher = {Gauthier-Villars},
     number = {25},
     year = {1927},
     language = {fr},
     url = {http://www.numdam.org/item/MSM_1927__25__1_0/}
}