To cite package ‘pdfminer’ in publications use:

Schwendinger F, Schwendinger B (2020). pdfminer: Read Portable Document Format (PDF) Files. R package version 1.0, https://CRAN.R-project.org/package=pdfminer.

Corresponding BibTeX entry:

  @Manual{,
    title = {pdfminer: Read Portable Document Format (PDF) Files},
    author = {Florian Schwendinger and Benjamin Schwendinger},
    year = {2020},
    note = {R package version 1.0},
    url = {https://CRAN.R-project.org/package=pdfminer},
  }