@article{03979382, title = {The semigroup of nonempty finite subsets of integers.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {9}, year = {1986}, pages = {605-616}, doi = {10.1155/S0161171286000765}, zbl = {0606.20057}, language = {en}, url = {http://dml.mathdoc.fr/item/03979382} }
Spake, Reuben. The semigroup of nonempty finite subsets of integers.. International Journal of Mathematics and Mathematical Sciences, Tome 9 (1986) pp. 605-616. doi : 10.1155/S0161171286000765. http://gdmltest.u-ga.fr/item/03979382/