@article{AM2_1975__12_136482,
     author = {Dietrich Braess},
     title = {On the {Degree} of {Approximation} by {Spline} {Functions} with {Free} {Knots.}},
     journal = {Aequationes mathematicae},
     pages = {80--81},
     publisher = {mathdoc},
     volume = {12},
     year = {1975},
     zbl = {0328.41012},
     url = {http://geodesic.mathdoc.fr/item/AM2_1975__12_136482/}
}