@article{ding_li_huang_yang_li_blaabjerg_2018, 
  title={A Hierarchical Modeling for Reactive Power Optimization With Joint Transmission and Distribution Networks by Curve Fitting}, 
  volume={12}, 
  DOI={10.1109/jsyst.2016.2642218}, 
  publisher={Institute of Electrical and Electronics Engineers (IEEE)}, 
  author={Ding and Li and Huang and Yang and Li and Blaabjerg}, 
  year={2018}
  }