@article{DAN_1975_223_4_a0,
     author = {Yu. A. Alpin and R. G. Bukharaev},
     title = {A sufficiency test for nonrepresentability of languages in finite-state probabilistic automata},
     journal = {Doklady Akademii Nauk},
     pages = {777--780},
     publisher = {mathdoc},
     volume = {223},
     number = {4},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1975_223_4_a0/}
}