@article{PDM_2012_3_a4,
     author = {S. M. Ratseev},
     title = {About perfect imitation resistant ciphers},
     journal = {Prikladna\^a diskretna\^a matematika},
     pages = {41--46},
     publisher = {mathdoc},
     number = {3},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDM_2012_3_a4/}
}