@article{MZ_1919__5_167554,
     author = {E., Landau},
     title = {\"Uber die {Gitterpunkte} in einem {Kreise}},
     journal = {Mathematische Zeitschrift},
     pages = {319--320},
     publisher = {mathdoc},
     volume = {5},
     year = {1919},
     zbl = {47.0157.03},
     url = {http://geodesic.mathdoc.fr/item/MZ_1919__5_167554/}
}