@article{MT_1989_12_a0,
     author = {N. V. Beljakin},
     title = {Computations with oracles},
     journal = {Matemati\v{c}eskie trudy},
     pages = {4--24},
     publisher = {mathdoc},
     volume = {12},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_1989_12_a0/}
}