@article{BSMA_1876__11__233_1,
     author = {Beltrami, E.},
     title = {Formules fondamentales de cin\'ematique dans les espaces de courbure constante},
     journal = {Bulletin des Sciences Math\'ematiques et Astronomiques},
     pages = {233--240},
     publisher = {Gauthier-Villars},
     volume = {11},
     year = {1876},
     language = {fr},
     url = {http://www.numdam.org/item/BSMA_1876__11__233_1/}
}