@article{MZ_1964__85_170285,
     author = {M.M. Robertson},
     title = {Integrability of trigonometric series. {II.}},
     journal = {Mathematische Zeitschrift},
     pages = {62--67},
     publisher = {mathdoc},
     volume = {85},
     year = {1964},
     zbl = {0133.02401},
     url = {http://geodesic.mathdoc.fr/item/MZ_1964__85_170285/}
}