[B-T] BUKOR J.-TÓTH J. T.:
On accumulation points of ratio sets of positive integers. Amer. Math. Monthly 103 (199G), 502 504.
MR 1390582
[G] GREKOS G.:
Densitгes in disjoint unions. Math. Slovaca 49 (1999), 255-262.
MR 1728237
[S-Tl] STRAUCH O.-TÓTH J. T.:
Asymptotic density of $A \subset N$ and density of the ratio set $R(A)$. Acta Arith. 87 (1998), 67-78.
MR 1659159
[S-T2] STRAUCH O.-TÓTH J. T :
Distribution functions of ratio sequences. Publ. Math. Debrecen 58 (2001), 751-778.
MR 1828725 |
Zbl 1183.11042