To cite package ‘motifmatchr’ in publications use:

  Schep A (2017). _motifmatchr: Fast Motif Matching in R_. R package
  version 1.27.0, <https://bioconductor.org/packages/motifmatchr>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {motifmatchr: Fast Motif Matching in R},
    author = {Alicia Schep},
    year = {2017},
    note = {R package version 1.27.0},
    url = {https://bioconductor.org/packages/motifmatchr},
  }