@article{GDZPPN00230600X, title = {Markoff Forms and Primitive Words.}, journal = {Mathematische Annalen}, volume = {196}, year = {1972}, pages = {8-22}, zbl = {0227.10018}, url = {http://dml.mathdoc.fr/item/GDZPPN00230600X} }
Cohn, Harvey. Markoff Forms and Primitive Words.. Mathematische Annalen, Tome 196 (1972) pp. 8-22. http://gdmltest.u-ga.fr/item/GDZPPN00230600X/