@article{AL_1982_21_6_a6,
     author = {D. M. Smirnov},
     title = {Universal definability of {Mal'tsev} classes},
     journal = {Algebra i logika},
     pages = {721--738},
     year = {1982},
     volume = {21},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1982_21_6_a6/}
}