@article{AL_1973_12_1_a4,
     author = {A. I. Omarov},
     title = {Subsystems of reduced powers},
     journal = {Algebra i logika},
     pages = {74--82},
     year = {1973},
     volume = {12},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1973_12_1_a4/}
}