@article{AL_1972_11_3_a0,
     author = {V. V. V'yugin},
     title = {Discrete classes of recursively enumerable sets},
     journal = {Algebra i logika},
     pages = {243--256},
     publisher = {mathdoc},
     volume = {11},
     number = {3},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1972_11_3_a0/}
}