@article{MZ_1943__49_169052,
     author = {G. Lorentz},
     title = {\"Uber die {Mittelwerte} der {Funktionen} eines {Orthogonalsystems}},
     journal = {Mathematische Zeitschrift},
     pages = {724--733},
     publisher = {mathdoc},
     volume = {49},
     year = {1943},
     zbl = {0028.39202},
     url = {http://geodesic.mathdoc.fr/item/MZ_1943__49_169052/}
}