@article{1986-hildebrand-rho
,author={Adolf Hildebrand}
,ISSN={0022--314X}
,journal={Journal of Number Theory}
,MR={87d:11066}
,pages={289--307}
,title={{On the number of positive integers $\le x$ and free of prime factors $>y$}}
,volume={22}
,year={1986}
}