@article{MZM_2012_91_6_a4,
     author = {V. G. Kanovei and V. A. Lyubetskii},
     title = {Effective {Compactness} and {Sigma-Compactness}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {840--852},
     publisher = {mathdoc},
     volume = {91},
     number = {6},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2012_91_6_a4/}
}