@article{AL_1969_8_3_a3,
     author = {G. T. Kozlov and A. I. Kokorin},
     title = {An elementary theory of torsion-free abelian groups with a},
     journal = {Algebra i logika},
     pages = {320--334},
     publisher = {mathdoc},
     volume = {8},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1969_8_3_a3/}
}