@article{bwmeta1.element.bwnjournal-article-aav12i4p321bwm,
author = {Alexander, Ralph},
title = {Density and multiplicative structure of sets of integers},
journal = {Acta Arithmetica},
volume = {12},
year = {1967},
pages = {321-332},
zbl = {0189.04404},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-aav12i4p321bwm}
}
Alexander, Ralph. Density and multiplicative structure of sets of integers. Acta Arithmetica, Tome 12 (1967) pp. 321-332. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-aav12i4p321bwm/