@article{MZ_1991__208_3_174296,
     author = {R. Brussee and G.J. Heckmann and E.M. Opdam},
     title = {Variation on a theme of {MacDonald.}},
     journal = {Mathematische Zeitschrift},
     pages = {1--10},
     publisher = {mathdoc},
     volume = {208},
     number = {3},
     year = {1991},
     zbl = {0763.33006},
     url = {http://geodesic.mathdoc.fr/item/MZ_1991__208_3_174296/}
}