@article{SLC_1989_21_a0,
     author = {Andreas Dress and Johannes Grabmeier},
     title = {On zero-testing and interpolation of sums of characters},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1989},
     volume = {21},
     url = {http://geodesic.mathdoc.fr/item/SLC_1989_21_a0/}
}