@article{BSMF_1939__67__132_0,
     author = {De Losada y Puga, Cristobal},
     title = {Sur la trigonom\'etrie des petits triangles curvilignes plans},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {132--136},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {67},
     year = {1939},
     doi = {10.24033/bsmf.1296},
     zbl = {0023.07001},
     language = {fr},
     url = {http://www.numdam.org/item/BSMF_1939__67__132_0/}
}

De Losada y Puga, Cristobal. Sur la trigonométrie des petits triangles curvilignes plans. Bulletin de la Société Mathématique de France, Tome 67 (1939) , pp. 132-136. doi : 10.24033/bsmf.1296. http://www.numdam.org/item/BSMF_1939__67__132_0/