@article{AL_1998_37_3_a0,
     author = {N. V. Bayanova},
     title = {Coverings in the lattice of varieties of $l$-groups},
     journal = {Algebra i logika},
     pages = {253--269},
     publisher = {mathdoc},
     volume = {37},
     number = {3},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1998_37_3_a0/}
}