For use of the nondetects package, please cite:

  McCall MN, McMurray H, Land H, Almudevar A (2014). On Non-detects in
  qPCR Data.

A BibTeX entry for LaTeX users is

  @Article{,
    author = {Matthew N McCall and Helene McMurray and Hartmut Land and Anthony Almudevar},
    title = {On Non-detects in qPCR Data},
    journal = {Bioinformatics},
    year = {2014},
  }