@article{SF_1993__47_2_135279,
     author = {A.V. Kelarev},
     title = {On semigroup graded {PI-algebras.}},
     journal = {Semigroup forum},
     pages = {294--298},
     publisher = {mathdoc},
     volume = {47},
     number = {2},
     year = {1993},
     zbl = {0808.16048},
     url = {http://geodesic.mathdoc.fr/item/SF_1993__47_2_135279/}
}