@article{ZNSL_1971_20_a18,
     author = {A. O. Slisenko},
     title = {A~property of recursively enumerable sets containing ``hardly deducible'' formulas},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {200--207},
     publisher = {mathdoc},
     volume = {20},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_20_a18/}
}