@article{IVM_1982_11_a3,
     author = {\`E. A. Golubov and M. V. Sapir},
     title = {Varieties of finitely approximable semigroups},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {21--29},
     publisher = {mathdoc},
     number = {11},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1982_11_a3/}
}