To cite CR2 in publications use:

Huang F., & Li, X. (2022). Using cluster robust standard errors when analyzing group randomized trials with few clusters. Behavior Research Methods, 54, 1181-1199.

Huang F., & Zhang, B. (2022). CR2: Compute cluster robust standard errors with degrees of freedom adjustments https://CRAN.R-project.org/package=CR2

Corresponding BibTeX entries:

  @Article{,
    title = {Using cluster robust standard errors when analyzing group
      randomized trials with few clusters},
    author = {Francis Huang and Xintong Li},
    journal = {Behavior Research Methods},
    year = {2022},
    url =
      {https://link.springer.com/epdf/10.3758/s13428-021-01627-0?sharing_token=eIiUEDO3RA7xQuhBbPCeDZAH0g46feNdnc402WrhzypnhGrDXEDh-Uq8KAb789impq-2g25kEJJoCmKwEsXVbXuLkfLHza-JzNwtSCVJlJmHuydDfYKExT_sbRuNeHthDaXyIsjKk9tCd9jOuK4Px2WocvDFoVOyuV-5G7LSq_U%3D},
  }

  @Manual{,
    title = {CR2: Compute cluster robust standard errors with degrees
      of freedom adjustments},
    author = {Francis Huang and Bixi Zhang},
    note = {R package version 0.1.1},
    url = {https://CRAN.R-project.org/package=CR2},
  }