To cite package ‘pcr’ in publications use:

  Ahmed M, Kim DR. 2018. pcr: an R package for quality assessment,
  analysis and testing of qPCR data. PeerJ 6:e4473
  https://doi.org/10.7717/peerj.4473

A BibTeX entry for LaTeX users is

  @Article{,
    title = {pcr: an R package for quality assessment, analysis and testing of qPCR data},
    author = {Mahmoud Ahmed and Deok Ryong Kim},
    year = {2018},
    journal = {PeerJ},
    doi = {10.7717/peerj.4473},
    volume = {6},
    pages = {e4473},
  }