@article{GDZPPN001262262, title = {Free products with amalgamation of semigroups.}, journal = {Semigroup forum}, volume = {46}, year = {1993}, pages = {54-61}, zbl = {0802.20048}, url = {http://dml.mathdoc.fr/item/GDZPPN001262262} }
Dekov, D.V. Free products with amalgamation of semigroups.. Semigroup forum, Tome 46 (1993) pp. 54-61. http://gdmltest.u-ga.fr/item/GDZPPN001262262/