@article{RM_1974_29_6_a7,
     author = {M. S. Burgin},
     title = {Free products in varieties of groups},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {29},
     number = {6},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1974_29_6_a7/}
}