@article{MZ_1928__27_167995,
     author = {G. H., und J. Hardy and J. E. Littlewood},
     title = {Some properties of fractional integrals. {I.}},
     journal = {Mathematische Zeitschrift},
     pages = {565--606},
     publisher = {mathdoc},
     volume = {27},
     year = {1928},
     zbl = {54.0275.05},
     url = {http://geodesic.mathdoc.fr/item/MZ_1928__27_167995/}
}