1. K. Alladi andP. Erdös, On the asymptotic behaviour of large prime factors of integers. Pacific J. Math.82, 295?315 (1979).
2. N. G. de Bruijn, The asymptotic behaviour of a function occurring in the theory of primes. J. Indian Math. Soc. (N.S.)15, 25?32 (1951).
3. N. G. de Bruijn, On the number of integers ?x and free of prime factors >y. Nederl. Akad. Wetensch. Proc. Ser. A54=Indag. Math.13, 50?60 (1951).
4. J.-M. De Koninck andA. Ivi?, Topics in arithmetical functions. Math. Studies43, North-Holland, Amsterdam 1980.
5. P. Erdös andA. Ivi?, Estimates for sums involving the largest prime factor of an integer and certain related additive functions. Studia Sci. Math. Hungar.15, 183?199 (1980).