@article{AL_2000_39_1_a1,
     author = {V. A. Gorbunov and A. V. Kravchenko},
     title = {Universal {Horn} classes and antivarieties of algebraic systems},
     journal = {Algebra i logika},
     pages = {3--22},
     year = {2000},
     volume = {39},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2000_39_1_a1/}
}