@article{AM2_1992__44_1_137494,
     author = {E.W. Cheney and Xingping Sun},
     title = {The fundamentality of sets of ridge functions.},
     journal = {Aequationes mathematicae},
     pages = {226--235},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1992},
     zbl = {0766.41036},
     url = {http://geodesic.mathdoc.fr/item/AM2_1992__44_1_137494/}
}