@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/