To cite package 'AGD' in publications use:

van Buuren S (2018). AGD: Analysis of Growth Data. R package version 0.39, https://CRAN.R-project.org/package=AGD.

Corresponding BibTeX entry:

  @Manual{AGD-package,
    title = {AGD: Analysis of Growth Data},
    author = {Stef {van Buuren}},
    year = {2018},
    note = {R package version 0.39},
    url = {https://CRAN.R-project.org/package=AGD},
  }