@article{MZ_1931__33_168287,
     author = {A., Walfisz},
     title = {\"Uber einige trigonometrische {Summen}},
     journal = {Mathematische Zeitschrift},
     pages = {564--601},
     publisher = {mathdoc},
     volume = {33},
     year = {1931},
     zbl = {0001.39001},
     url = {http://geodesic.mathdoc.fr/item/MZ_1931__33_168287/}
}