@article{1029000032, author = {Knapp, A. W.}, title = {Doubly generated Fuchsian groups.}, journal = {Michigan Math. J.}, volume = {15}, number = {1}, year = {1968}, pages = { 289-304}, language = {en}, url = {http://dml.mathdoc.fr/item/1029000032} }
Knapp, A. W. Doubly generated Fuchsian groups.. Michigan Math. J., Tome 15 (1968) no. 1, pp. 289-304. http://gdmltest.u-ga.fr/item/1029000032/