@article{SF_1979__17_134326,
     author = {Z. Shmuely},
     title = {Idempotents in completely {PO} semigroups.},
     journal = {Semigroup forum},
     pages = {317--324},
     year = {1979},
     volume = {17},
     zbl = {0429.06004},
     url = {http://geodesic.mathdoc.fr/item/SF_1979__17_134326/}
}