@article{AL_1983_22_6_a5,
     author = {V. L. Selivanov},
     title = {Hierarchies of hyperarithmetic sets and functions},
     journal = {Algebra i logika},
     pages = {666--692},
     publisher = {mathdoc},
     volume = {22},
     number = {6},
     year = {1983},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1983_22_6_a5/}
}