To cite Ball in publications use:

Zhu J, Pan W, Zheng W, Wang X (2021). “Ball: An R Package for Detecting Distribution Difference and Association in Metric Spaces.” Journal of Statistical Software, 97(6), 1–31. doi:10.18637/jss.v097.i06.

Corresponding BibTeX entry:

  @Article{,
    title = {{Ball}: An {R} Package for Detecting Distribution
      Difference and Association in Metric Spaces},
    author = {Jin Zhu and Wenliang Pan and Wei Zheng and Xueqin Wang},
    journal = {Journal of Statistical Software},
    year = {2021},
    volume = {97},
    number = {6},
    pages = {1--31},
    doi = {10.18637/jss.v097.i06},
  }