@article{GDZPPN002321394, title = {Maass Operators and Eisenstein Series.}, journal = {Mathematische Annalen}, volume = {255}, year = {1981}, pages = {135-144}, zbl = {0455.10018}, url = {http://dml.mathdoc.fr/item/GDZPPN002321394} }
Harris, Michael. Maass Operators and Eisenstein Series.. Mathematische Annalen, Tome 255 (1981) pp. 135-144. http://gdmltest.u-ga.fr/item/GDZPPN002321394/