@article{GDZPPN001260146, title = {Factorization problems in semigroups.}, journal = {Semigroup forum}, volume = {40}, year = {1990}, pages = {23-38}, zbl = {0693.20063}, url = {http://dml.mathdoc.fr/item/GDZPPN001260146} }
Geroldinger, A.; Lettl, G. Factorization problems in semigroups.. Semigroup forum, Tome 40 (1990) pp. 23-38. http://gdmltest.u-ga.fr/item/GDZPPN001260146/