@article{GDZPPN002182831,
title = {Trigonometric series with non-negative partial sums.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {229},
year = {1968},
pages = {163-169},
zbl = {0174.10003},
url = {http://dml.mathdoc.fr/item/GDZPPN002182831}
}
Shah, S.M.; Chidambaraswamy, J. Trigonometric series with non-negative partial sums.. Journal für die reine und angewandte Mathematik, Tome 229 (1968) pp. 163-169. http://gdmltest.u-ga.fr/item/GDZPPN002182831/