@article{MZ_1988__197_1_183719,
     author = {G\"unter K\"ohler},
     title = {Theta {Series} on the {Hecke} {Groups} {G(...2)} and {G(...3).}},
     journal = {Mathematische Zeitschrift},
     pages = {69--96},
     publisher = {mathdoc},
     volume = {197},
     number = {1},
     year = {1988},
     zbl = {0632.10024},
     url = {http://geodesic.mathdoc.fr/item/MZ_1988__197_1_183719/}
}