@article{AL_1973_12_5_a1,
     author = {V. V. V'yugin},
     title = {Certain examples of upper semilattices of computable numerations},
     journal = {Algebra i logika},
     pages = {512--529},
     publisher = {mathdoc},
     volume = {12},
     number = {5},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1973_12_5_a1/}
}