@article{DAN_1989_307_2_a9,
     author = {A. V. Pokrovskii},
     title = {Measures of unpredictability of binary sequences},
     journal = {Doklady Akademii Nauk},
     pages = {300--303},
     publisher = {mathdoc},
     volume = {307},
     number = {2},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_307_2_a9/}
}