@article{AL_1963_2_5_a3,
     author = {Yu. L. Ershov and M. A. Taitslin},
     title = {Undecidability of certain theories},
     journal = {Algebra i logika},
     pages = {37--41},
     publisher = {mathdoc},
     volume = {2},
     number = {5},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1963_2_5_a3/}
}