@article{GDZPPN001258656,
title = {On numerical semigroups.},
journal = {Semigroup forum},
volume = {33},
year = {1986},
pages = {63-84},
zbl = {0614.10046},
url = {http://dml.mathdoc.fr/item/GDZPPN001258656}
}
Häggkvist, R.; Fröberg, R.; Gottlieb, C. On numerical semigroups.. Semigroup forum, Tome 33 (1986) pp. 63-84. http://gdmltest.u-ga.fr/item/GDZPPN001258656/