@article{VMUMM_1998_3_a2,
     author = {R. I. Grigorchuk and A. M. Stepin},
     title = {On amenability of semigroups with cancellation},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {12--16},
     publisher = {mathdoc},
     number = {3},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1998_3_a2/}
}