@inproceedings{lehmann2012dynamical,
  title={Dynamical classes of collective attention in twitter},
  author={Lehmann, Janette and Gon{\c{c}}alves, Bruno and Ramasco, Jos{\'e} J and Cattuto, Ciro},
  booktitle={Proceedings of the 21st international conference on World Wide Web},
  pages={251--260},
  year={2012},
  organization={ACM}
}