@article{IVM_2008_12_a3,
     author = {N. Kehayopulu and M. Tsingelis},
     title = {Ordered semigroups having the $P$-property},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {28--33},
     publisher = {mathdoc},
     number = {12},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2008_12_a3/}
}