@article{NUMA_1959__1_131433,
     author = {P.C. SIKKEMA},
     title = {\"Uber den {Grad} der {Approximation} mit {Bernstein-Polynomen.}},
     journal = {Numerische Mathematik},
     pages = {221--239},
     publisher = {mathdoc},
     volume = {1},
     year = {1959},
     zbl = {0089.27503},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1959__1_131433/}
}