To cite package ‘hbal’ in publications use:

  Xu Y, Yang E (2025). _hbal: Hierarchically Regularized Entropy
  Balancing_. R package version 1.2.15,
  <https://github.com/xuyiqing/hbal>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {hbal: Hierarchically Regularized Entropy Balancing},
    author = {Yiqing Xu and Eddie Yang},
    year = {2025},
    note = {R package version 1.2.15},
    url = {https://github.com/xuyiqing/hbal},
  }