@article{JDM_1926__35_145732,
     author = {S. Sidon},
     title = {Ein {Satz} \"uber positive harmonische {Polynome.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {97--98},
     publisher = {mathdoc},
     volume = {35},
     year = {1926},
     zbl = {52.0490.03},
     url = {http://geodesic.mathdoc.fr/item/JDM_1926__35_145732/}
}