@article{AM2_1997__54_3_137694,
     author = {M. Felten},
     title = {A modulus of smoothness based on an algebraic addition.},
     journal = {Aequationes mathematicae},
     pages = {56--73},
     publisher = {mathdoc},
     volume = {54},
     number = {3},
     year = {1997},
     zbl = {0882.41008},
     url = {http://geodesic.mathdoc.fr/item/AM2_1997__54_3_137694/}
}