@article{VMUMM_1983_3_a4,
     author = {L. A. Skornyakov},
     title = {Schreier and {Hall} varieties of unary algebras},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {24--28},
     publisher = {mathdoc},
     number = {3},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1983_3_a4/}
}