@inproceedings{ballagas2007rexplorer,
  title={REXplorer: a mobile, pervasive spell-casting game for tourists},
  author={Ballagas, Rafael A and Kratz, Sven and Borchers, Jan and Yu, Eugen and Walz, Steffen P and Fuhr, Claudia O and Hovestadt, Ludger and Tann, Martin},
  booktitle={CHI'07 extended abstracts on Human factors in computing systems},
  pages={1929--1934},
  Month={april},
  Year={2007},
  Organization={ACM}
}