To cite pcdreg, cite the paper for the method and the package for the
software you ran. The paper is the more important of the two.

  Sun D, Guo Y, Li Y, Tu W, Sun J (2024). “A robust approach for
  regression analysis of panel count data.” _Bernoulli_, *30*(4),
  3251-3275. doi:10.3150/23-BEJ1713
  <https://doi.org/10.3150/23-BEJ1713>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {A robust approach for regression analysis of panel count data},
    author = {Dayu Sun and Yuanyuan Guo and Yang Li and Wanzhu Tu and Jianguo Sun},
    journal = {Bernoulli},
    year = {2024},
    volume = {30},
    number = {4},
    pages = {3251--3275},
    doi = {10.3150/23-BEJ1713},
  }

  Sun D (2026). _pcdreg: Semiparametric Regression for Panel Count
  Data_. R package version 0.1.0, <https://github.com/dayusun/pcdreg>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {{pcdreg}: Semiparametric Regression for Panel Count Data},
    author = {Dayu Sun},
    year = {2026},
    note = {R package version 0.1.0},
    url = {https://github.com/dayusun/pcdreg},
  }