@article{GDZPPN002101645, title = {On cusp forms for co-finite subgroups of PSL(2, IR).}, journal = {Inventiones mathematicae}, volume = {82}, year = {1985}, pages = {339-364}, zbl = {0558.10017}, url = {http://dml.mathdoc.fr/item/GDZPPN002101645} }
Sarnak, P.; Phillips, R.S. On cusp forms for co-finite subgroups of PSL(2, IR).. Inventiones mathematicae, Tome 82 (1985) pp. 339-364. http://gdmltest.u-ga.fr/item/GDZPPN002101645/