@article{DAN_1972_204_5_a3,
     author = {Yu. L. Ershov},
     title = {Existence of constructivizations},
     journal = {Doklady Akademii Nauk},
     pages = {1041--1044},
     publisher = {mathdoc},
     volume = {204},
     number = {5},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_204_5_a3/}
}