@article{wu2015telcovis,
  title={Telcovis: Visual exploration of co-occurrence in urban human mobility based on telco data},
  author={Wu, Wenchao and Xu, Jiayi and Zeng, Haipeng and Zheng, Yixian and Qu, Huamin and Ni, Bing and Yuan, Mingxuan and Ni, Lionel M},
  journal={IEEE Transactions on Visualization and Computer Graphics},
  volume={22},
  number={1},
  pages={935--944},
  year={2015},
  publisher={IEEE}
}