@article{BSMF_1909__37__51_0,
     author = {Goursat, \'Edouard},
     title = {Sur les surfaces \`a courbure constante n\'egative},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {37},
     year = {1909},
     pages = {51-58},
     doi = {10.24033/bsmf.835},
     language = {fr},
     url = {http://www.numdam.org/item/BSMF_1909__37__51_0}
}

Goursat, E. Sur les surfaces à courbure constante négative. Bulletin de la Société Mathématique de France, Volume 37 (1909) , pp. 51-58. doi : 10.24033/bsmf.835. http://www.numdam.org/item/BSMF_1909__37__51_0/