@article{MZ_1921__11_167660,
     author = {O. Siegel},
     title = {Darstellung total positiver {Zahlen} durch {Quadrate}},
     journal = {Mathematische Zeitschrift},
     pages = {246--275},
     publisher = {mathdoc},
     volume = {11},
     year = {1921},
     zbl = {48.0179.04},
     url = {http://geodesic.mathdoc.fr/item/MZ_1921__11_167660/}
}