@article{MZ_1964__83_170218,
     author = {M.M. Robertson},
     title = {Integrability of trigonometric series.},
     journal = {Mathematische Zeitschrift},
     pages = {119--122},
     year = {1964},
     volume = {83},
     zbl = {0119.05702},
     url = {http://geodesic.mathdoc.fr/item/MZ_1964__83_170218/}
}