On the number of semigroups of natural numbers.
Mathematica Scandinavica, Tome 66 (1990) no. 1, pp. 197-215
@article{MS2_1990__66_1_167105,
author = {J\"orgen Backelin},
title = {On the number of semigroups of natural numbers.},
journal = {Mathematica Scandinavica},
pages = {197--215},
year = {1990},
volume = {66},
number = {1},
zbl = {0741.11006},
url = {http://geodesic.mathdoc.fr/item/MS2_1990__66_1_167105/}
}
Jörgen Backelin. On the number of semigroups of natural numbers.. Mathematica Scandinavica, Tome 66 (1990) no. 1, pp. 197-215. http://geodesic.mathdoc.fr/item/MS2_1990__66_1_167105/