@article{AL_1967_6_5_a0,
     author = {Yu. L. Ershov},
     title = {Elementary theories of {Post} varieties},
     journal = {Algebra i logika},
     pages = {7--15},
     publisher = {mathdoc},
     volume = {6},
     number = {5},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1967_6_5_a0/}
}