@ARTICLE{chen2019virtual,
  author={Qi Chen and Yuxiang Sun and Min Zhao and Ming Liu},  
  journal={IEEE Access}, 
  title={A Virtual Structure Formation Guidance Strategy for Multi-Parafoil Systems}, 
  year={2019},
  volume={7},
  number={},
  pages={123592-123603},
  doi={10.1109/ACCESS.2019.2938078}}