@article{MAN_1981__258_163583,
     author = {Michael Harris},
     title = {Maass {Operators} and {Eisenstein} {Series.}},
     journal = {Mathematische Annalen},
     pages = {135--144},
     year = {1981},
     volume = {258},
     zbl = {0455.10018},
     url = {http://geodesic.mathdoc.fr/item/MAN_1981__258_163583/}
}