@article{JRAM_1968__229_150840,
     author = {S.M. Shah and J. Chidambaraswamy},
     title = {Trigonometric series with non-negative partial sums.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {163--169},
     publisher = {mathdoc},
     volume = {229},
     year = {1968},
     zbl = {0174.10003},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1968__229_150840/}
}