To cite KFAS in publications use:

Jouni Helske (2017). KFAS: Exponential Family State Space Models in R. Journal of Statistical Software, 78(10), 1-39.<doi:10.18637/jss.v078.i10>

Corresponding BibTeX entry:

  @Article{,
    title = {{KFAS}: Exponential Family State Space Models in {R}},
    author = {Jouni Helske},
    journal = {Journal of Statistical Software},
    year = {2017},
    volume = {78},
    number = {10},
    pages = {1--39},
    doi = {10.18637/jss.v078.i10},
  }