@article{GDZPPN002485338, title = {Naturally Orderd Transformation Semigroups.}, journal = {Monatshefte f\"ur Mathematik}, volume = {102}, year = {1986}, pages = {115-138}, zbl = {0594.20062}, url = {http://dml.mathdoc.fr/item/GDZPPN002485338} }
Kowol, G.; Mitsch, H. Naturally Orderd Transformation Semigroups.. Monatshefte für Mathematik, Tome 102 (1986) pp. 115-138. http://gdmltest.u-ga.fr/item/GDZPPN002485338/