To cite fastmatrix in publications use:

Osorio F, Ogueda A (2020). Fast computation of some matrices useful in statistics. R package version 0.2-3571, https://faosorios.github.io/fastmatrix/.

Corresponding BibTeX entry:

  @Manual{,
    title = {Fast computation of some matrices useful in statistics},
    author = {F. Osorio and A. Ogueda},
    year = {2020},
    note = {R package version 0.2-3571},
    url = {https://faosorios.github.io/fastmatrix/},
  }