To cite growfunctions in publications use:

Terrance D. Savitsky (2016). Bayesian Nonparametric Mixture Estimation for Time-Indexed Functional Data in R. Journal of Statistical Software, 72(2), 1-34.<doi:10.18637/jss.v072.i02>

Corresponding BibTeX entry:

  @Article{,
    title = {Bayesian Nonparametric Mixture Estimation for Time-Indexed
      Functional Data in {R}},
    author = {Terrance D. Savitsky},
    journal = {Journal of Statistical Software},
    year = {2016},
    volume = {72},
    number = {2},
    pages = {1--34},
    doi = {10.18637/jss.v072.i02},
  }