@article{FPM_2008_14_7_a9,
     author = {I. B. Kozhukhov and V. A. Yaroshevich},
     title = {Transformation semigroups preserving a~binary relation},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {129--135},
     publisher = {mathdoc},
     volume = {14},
     number = {7},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2008_14_7_a9/}
}