@article{SF_1996__53_2_135486,
     author = {A. Umar},
     title = {Semigroups of order-decreasing transformations: the isomorphism theorem.},
     journal = {Semigroup forum},
     pages = {220--224},
     publisher = {mathdoc},
     volume = {53},
     number = {2},
     year = {1996},
     zbl = {0858.20056},
     url = {http://geodesic.mathdoc.fr/item/SF_1996__53_2_135486/}
}