@article{MZM_1999_65_5_a6,
     author = {D. I. Piontkovskii},
     title = {On free products in varieties of associative algebras},
     journal = {Matemati\v{c}eskie zametki},
     pages = {693--702},
     year = {1999},
     volume = {65},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1999_65_5_a6/}
}