To cite package 'RCAL' in publications use:

  Tan, Z. and Sun, B. (2020). RCAL: Regularized calibrated estimation.
  R package version 2.0.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {RCAL: Regularized calibrated estimation},
    author = {Zhiqiang Tan and Baoluo Sun},
    year = {2020},
    note = {R package version 2.0},
  }