@inproceedings{stringhini12:poultry,
  title={{Poultry Markets: On the Underground Economy of Twitter Followers}},
  author={Gianluca Stringhini and Manuel Egele and Christopher Kruegel and Giovanni Vigna},
  booktitle={Proceedings of the Workshop on Online Social Networks (WOSN)},
  address={Helsinki, Finland},
  month={August},
  year={2012}
}