@article{AL_1985_24_5_a0,
     author = {Yu. L. Ershov},
     title = {$\Sigma$-predicates of finite types over an admissible set},
     journal = {Algebra i logika},
     pages = {499--536},
     year = {1985},
     volume = {24},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1985_24_5_a0/}
}