@article{JRAM_1991__414_153303,
     author = {Paul Ponomarev},
     title = {Theta series mod p and the basis problem for {Nebentypus.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {131--140},
     publisher = {mathdoc},
     volume = {414},
     year = {1991},
     zbl = {0715.11020},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1991__414_153303/}
}