@article{10_1017_S0017089500005498,
     author = {Grupp, F.},
     title = {On {Dirichlet} series attached to cusp forms and the {Siegel-zero}},
     journal = {Glasgow mathematical journal},
     pages = {107--119},
     year = {1984},
     volume = {25},
     number = {1},
     doi = {10.1017/S0017089500005498},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500005498/}
}