@article{UZKU_2012_154_2_a17,
     author = {K. P. Shum and X. M. Ren and C. M. Gong},
     title = {On constructions of semigroups},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {180--195},
     year = {2012},
     volume = {154},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2012_154_2_a17/}
}