@inproceedings{variablefidelityexpectedimprovementmetho,
  title = {Variable-fidelity expected improvement method for efficient global optimization of expensive functions},
  author = {Yu Zhang and Zhong-Hua Han and Ke-Shi Zhang},
  year = {2018},
  booktitle = {Structural and Multidisciplinary Optimization 2018 5},
  url = {https://link-springer-com-s.libyc.nudt.edu.cn/article/10.1007/s00158-018-1971-x},
}