@article{improvecaptchassecurityusinggaussianblur,
  title = {Improve CAPTCHA's Security Using Gaussian Blur Filter},
  author = {Ariyan Zarei},
  year = {2014},
  eprint = {1410.4441},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1410.4441v1},
}