@article{AL_1985_24_4_a4,
     author = {A. V. Chagrov},
     title = {Varieties of logical matrices},
     journal = {Algebra i logika},
     pages = {426--489},
     year = {1985},
     volume = {24},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1985_24_4_a4/}
}