@article{GDZPPN001264443,
title = {Nearly prime subsemigroups of \ss N.},
journal = {Semigroup forum},
volume = {51},
year = {1995},
pages = {299-318},
zbl = {0843.22005},
url = {http://dml.mathdoc.fr/item/GDZPPN001264443}
}
Hindman, N.; Strauss, D. Nearly prime subsemigroups of ßN.. Semigroup forum, Tome 51 (1995) pp. 299-318. http://gdmltest.u-ga.fr/item/GDZPPN001264443/