| References: [1] Von Ahn, M. Blum., Langford, J. (2004). Telling Humans and Computers Apart Automatically, Communication of ACM, 47 (2), p 47-60, 2004.
[2] The CAPTCHA test. http://en.wikipedia.org/wiki/CAPTCHA
[3] von Ahn, L., Blum, M., Hopper, N., Langford, J. (2003). CAPTCHA: Using Hard AI Problems for Security, In: Proceedings of Eurocrypt, Warsaw, Poland, p 294-311, 2003.
[4] Baecher, P., Fischlin, M., Gordon, L., Langenberg, R., Lutzow, M., Schroder, D. (2010). CAPTCHAs: The Good, the Bad and the Ugly, Sicherheit, pp. 353-365, 2010.
[5] Brodic, D., Petrovska, S., Jevtic, M., Milivojevic, Z. N. (2016). The Influence of the CAPTCHA Types to its Solving Times, In: Proceeding of 39th MIPRO, Opatija, Croatia, p 1274-1277.
[6] Conover, W. J. (1999). Practical Nonparametric Statistical, p 428- 433, John Wiley & Sons, Inc. New York, 1999. |
