@article{AL_2004_43_6_a4,
     author = {A. G. Pinus},
     title = {Elementary {Equivalence} of {Derived} {Structures} of {Free} {Semigroups,} {Unars,} and {Groups}},
     journal = {Algebra i logika},
     pages = {730--748},
     publisher = {mathdoc},
     volume = {43},
     number = {6},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2004_43_6_a4/}
}