@article{1077475358,
author = {Ramaswami, V.},
title = {The number of positive integers $\leq x$ and free of prime
divisors $> x^c$ , and a problem of S. S. Pillai},
journal = {Duke Math. J.},
volume = {16},
number = {1},
year = {1949},
pages = { 99-109},
language = {en},
url = {http://dml.mathdoc.fr/item/1077475358}
}
Ramaswami, V. The number of positive integers $\leq x$ and free of prime
divisors $> x^c$ , and a problem of S. S. Pillai. Duke Math. J., Tome 16 (1949) no. 1, pp. 99-109. http://gdmltest.u-ga.fr/item/1077475358/