@article{ADM_2015_20_1_a3,
     author = {Vitaliy M. Bondarenko and Yaroslav V. Zaciha},
     title = {On characteristic properties of semigroups},
     journal = {Algebra and discrete mathematics},
     pages = {32--39},
     year = {2015},
     volume = {20},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ADM_2015_20_1_a3/}
}