@article{MAN_1981__258_163574,
     author = {Martin L. Karel},
     title = {Transformation {Theory} of {Eisenstein} {Series.}},
     journal = {Mathematische Annalen},
     pages = {1--10},
     publisher = {mathdoc},
     volume = {258},
     year = {1981},
     zbl = {0455.10017},
     url = {http://geodesic.mathdoc.fr/item/MAN_1981__258_163574/}
}