@article{AL_1971_10_5_a6,
     author = {A. B. Khutoretskii},
     title = {The power of the upper semilattice of computable numerations},
     journal = {Algebra i logika},
     pages = {561--569},
     publisher = {mathdoc},
     volume = {10},
     number = {5},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1971_10_5_a6/}
}