@article{GDZPPN00237319X, title = {Some properties of fractional integrals. II.}, journal = {Mathematische Zeitschrift}, volume = {34}, year = {1932}, pages = {403-439}, zbl = {0003.15601}, url = {http://dml.mathdoc.fr/item/GDZPPN00237319X} }
Hardy, G. H., and J.E.Littlewood,. Some properties of fractional integrals. II.. Mathematische Zeitschrift, Tome 34 (1932) pp. 403-439. http://gdmltest.u-ga.fr/item/GDZPPN00237319X/