@article{SEMR_2014_11_a18,
     author = {B. M. Vernikov and V. Yu. Shaprynskiǐ},
     title = {Three weaker variants of congruence permutability for semigroup varieties},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {567--604},
     publisher = {mathdoc},
     volume = {11},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2014_11_a18/}
}