@article{MZ_1990__205_3_174172,
     author = {E.J. Ditters},
     title = {Hilbert functions and {Witt} functions. {An} identity for congruences of {Atkin} and of {Swinnerton-Dyer} type.},
     journal = {Mathematische Zeitschrift},
     pages = {247--278},
     publisher = {mathdoc},
     volume = {205},
     number = {3},
     year = {1990},
     zbl = {0685.14026},
     url = {http://geodesic.mathdoc.fr/item/MZ_1990__205_3_174172/}
}