@article{GDZPPN001254588, title = {Left chain semigroups.}, journal = {Semigroup forum}, volume = {23}, year = {1981}, pages = {1-8}, zbl = {0459.20061}, url = {http://dml.mathdoc.fr/item/GDZPPN001254588} }
Kozhukhov, I.B. Left chain semigroups.. Semigroup forum, Tome 23 (1981) pp. 1-8. http://gdmltest.u-ga.fr/item/GDZPPN001254588/