@inproceedings{shirali2008dynamic,
  author    = {Shirali-Shahreza, M. and Shirali-Shahreza, S.},
  title     = {Dynamic {CAPTCHA}},
  booktitle = {Proceedings of the 2008 International Symposium on Communications and Information Technologies (ISCIT 2008)},
  address   = {Vientiane, Lao PDR},
  month     = oct,
  year      = {2008},
  pages     = {436--440},
  doi		= {10.1109/ISCIT.2008.4700230}
}