@article{1077304285, author = {Phillips, R. S. and Sarnak, P.}, title = {On the spectrum of the Hecke groups}, journal = {Duke Math. J.}, volume = {52}, number = {1}, year = {1985}, pages = { 211-221}, language = {en}, url = {http://dml.mathdoc.fr/item/1077304285} }
Phillips, R. S.; Sarnak, P. On the spectrum of the Hecke groups. Duke Math. J., Tome 52 (1985) no. 1, pp. 211-221. http://gdmltest.u-ga.fr/item/1077304285/