To cite package 'FMP' in publications use:

Waller, N. G. (2016). FMP: IRT estimation via filtered polynomial models. R package version 1.3.

Corresponding BibTeX entry:

  @Manual{,
    title = {FMP: IRT estimation via filtered polynomial models.},
    author = {Niels G. Waller},
    year = {2016},
    note = {version 1.4},
  }