@article{gonzalez2007community,
  title={Community structure and ethnic preferences in school friendship networks},
  author={Gonz{\'a}lez, Marta C and Herrmann, Hans J and Kert{\'e}sz, J and Vicsek, T},
  journal={Physica A: Statistical mechanics and its applications},
  volume={379},
  number={1},
  pages={307--316},
  year={2007},
  publisher={North-Holland}
}