@article{MMO_1971_25_a2,
     author = {G. K. Genov},
     title = {On the theory of operations on the class of all groups},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {59--82},
     publisher = {mathdoc},
     volume = {25},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1971_25_a2/}
}