@article{MAN_1879__15_156864,
     author = {Markoff},
     title = {Sur les formes quadratiques binaires ind\'efinies},
     journal = {Mathematische Annalen},
     pages = {381--406},
     year = {1879},
     volume = {15},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/MAN_1879__15_156864/}
}