@article{MAN_1882__19_156992,
     author = {Harnack},
     title = {Vereinfachung der {Beweise} in der {Theorie} der {Fourier'schen} {Reihe}},
     journal = {Mathematische Annalen},
     pages = {235--279},
     publisher = {mathdoc},
     volume = {19},
     year = {1882},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MAN_1882__19_156992/}
}