@article{GDZPPN001262807, title = {Affine semigroups and second duals.}, journal = {Semigroup forum}, volume = {46}, year = {1993}, pages = {130-132}, zbl = {0782.22002}, url = {http://dml.mathdoc.fr/item/GDZPPN001262807} }
Pym, J. Affine semigroups and second duals.. Semigroup forum, Tome 46 (1993) pp. 130-132. http://gdmltest.u-ga.fr/item/GDZPPN001262807/