@article{PDM_2011_13_a21,
     author = {M. B. Abrosimov and A. A. Matorin},
     title = {Reliability analysis of graphical {CAPTCHA-systems} by the example of {KCAPTCHA}},
     journal = {Prikladna\^a diskretna\^a matematika},
     pages = {40--41},
     publisher = {mathdoc},
     number = {13},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDM_2011_13_a21/}
}