@article{AL_1973_12_2_a5,
     author = {Yu. G. Penzin},
     title = {Undecidability of fields of rational functions over fields of},
     journal = {Algebra i logika},
     pages = {205--210},
     publisher = {mathdoc},
     volume = {12},
     number = {2},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1973_12_2_a5/}
}