@article{niu_zhao_wei_yuan_ji_2021, 
  title={Stress Field Changes before the <i>M</i><sub>S</sub>8.0 Wenchuan Earthquake}, 
  volume={13}, 
  DOI={10.4236/ns.2021.139036}, 
  number={09}, 
  publisher={Scientific Research Publishing, Inc.}, 
  author={Niu, Anfu and Zhao, Jing and Wei, Yan and Yuan, Zhengyi and Ji, Ping}, 
  year={2021}
  }