@article{MABA_1990_4_3-4_a6,
     author = {H. Mevissen and R. J. Nessel},
     title = {On the {Best} {Approximation} of {Riemann} {Integrable} {Functions} by {Trigonometric} {Polynomials}},
     journal = {Mathematica balkanica},
     pages = {289},
     publisher = {mathdoc},
     volume = {4},
     number = {3-4},
     year = {1990},
     url = {http://geodesic.mathdoc.fr/item/MABA_1990_4_3-4_a6/}
}