To cite grofit in publications use:

Matthias Kahm, Guido Hasenbrink, Hella Lichtenberg-Frate, Jost Ludwig, Maik Kschischo (2010). grofit: Fitting Biological Growth Curves with R. Journal of Statistical Software, 33(7), 1-21. URL http://www.jstatsoft.org/v33/i07/.

Corresponding BibTeX entry:

  @Article{,
    title = {{grofit}: Fitting Biological Growth Curves with {R}},
    author = {Matthias Kahm and Guido Hasenbrink and Hella
      Lichtenberg-Frat{'e} and Jost Ludwig and Maik Kschischo},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {33},
    number = {7},
    pages = {1--21},
    url = {http://www.jstatsoft.org/v33/i07/},
  }