@article{DAN_1968_182_6_a1,
     author = {J. M. Barzdi\c{n}\v{s}},
     title = {Complexity of programs which recognize whether natural numbers not exceeding $n$~belong to a recursively enumerable set},
     journal = {Doklady Akademii Nauk},
     pages = {1249--1252},
     publisher = {mathdoc},
     volume = {182},
     number = {6},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_182_6_a1/}
}