@article{1949-ramaswami
,author={V. Ramaswami}
,ISSN={0012--7094}
,journal={Duke Mathematical Journal}
,MR={10,597b}
,pages={99--109}
,title={{The number of positive integers $\le x$ and free of prime divisors $>x^c$, and a problem of S. S. Pillai}}
,volume={16}
,year={1949}
}