To cite the package drc in publications use:

Ritz, C. & Streibig, J. C. (2005) Bioassay Analysis using R. J. Statist. Software, Vol 12, Issue 5.

Corresponding BibTeX entry:

  @Article{,
    title = {Bioassay Analysis using R},
    author = {C. Ritz and J. C. Streibig},
    journal = {Journal of Statistical Software},
    volume = {12},
    issue = {5},
    year = {2005},
    url = {http://www.bioassay.dk},
  }