To cite package 'PAA' in publications use:

  Turewicz M, Ahrens M, May C, Marcus K, Eisenacher M. PAA: An
  R/Bioconductor package for biomarker discovery with protein
  microarrays. Bioinformatics (2016) 32 (10): 1577-1579.
  doi:10.1093/bioinformatics/btw037, PubMed PMID: 26803161.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {PAA: An R/Bioconductor package for biomarker discovery with protein microarrays},
    author = {Michael Turewicz and Maike Ahrens and Caroline May and Katrin Marcus and Martin Eisenacher},
    year = {2016},
    journal = {Bioinformatics},
    volume = {32},
    number = {10},
    pages = {1577-1579},
    doi = {10.1093/bioinformatics/btw037},
    url = {http://bioinformatics.oxfordjournals.org/content/early/2016/02/17/bioinformatics.btw037},
  }