@article{MZM_2012_91_3_a13,
     author = {A. P. Kombarov},
     title = {Remark on $\Sigma${-Products}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {467--469},
     publisher = {mathdoc},
     volume = {91},
     number = {3},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2012_91_3_a13/}
}