@article{AL_1979_18_3_a4,
     author = {Yu. N. Mal'tsev and A. A. Nechaev},
     title = {Critical rings and varieties of algebras},
     journal = {Algebra i logika},
     pages = {341--347},
     publisher = {mathdoc},
     volume = {18},
     number = {3},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1979_18_3_a4/}
}