@article{MZ_1980__175_173031,
     author = {Thomas A. Metzger},
     title = {On the {Non-Vanishing} of {Certain} {Poincar\'e} {Series.}},
     journal = {Mathematische Zeitschrift},
     pages = {165--170},
     publisher = {mathdoc},
     volume = {175},
     year = {1980},
     zbl = {0444.30036},
     url = {http://geodesic.mathdoc.fr/item/MZ_1980__175_173031/}
}