@article{MAN_1961__142_160831,
     author = {P.L. Butzer},
     title = {On {Some} {Theorems} of {Hardy,} {Littlewood} and {Titchmarsh.}},
     journal = {Mathematische Annalen},
     pages = {259--269},
     publisher = {mathdoc},
     volume = {142},
     year = {1961},
     zbl = {0133.06302},
     url = {http://geodesic.mathdoc.fr/item/MAN_1961__142_160831/}
}