@article{SLC_1985_12_a5,
     author = {Arne D\"ur and Ulrich Oberst},
     title = {Operations of the {Additive} {Group} on the {Affine} {Line} and {Umbral} {Calculus}},
     journal = {S\'eminaire lotharingien de combinatoire},
     publisher = {mathdoc},
     volume = {12},
     year = {1985},
     url = {http://geodesic.mathdoc.fr/item/SLC_1985_12_a5/}
}