To cite hhcartr in publications use:

Davies P (2020). HHCART(G) - A reflected feature space for CART. https://CRAN.R-project.org/package=hhcartr.

Corresponding BibTeX entry:

  @Manual{,
    title = {HHCART(G) - A reflected feature space for CART},
    author = {Phil Davies},
    year = {2020},
    url = {https://CRAN.R-project.org/package=hhcartr},
  }