To cite the 'pqsfinder' package in publications use:

  Hon J, Martinek T, Zendulka J, Lexa M. (2017) pqsfinder: an
  exhaustive and imperfection-tolerant search tool for potential
  quadruplex-forming sequences in R. Bioinformatics. 33(21), 3373-3379.
  https://doi.org/10.1093/bioinformatics/btx413

A BibTeX entry for LaTeX users is

  @Article{,
    title = {pqsfinder: an exhaustive and imperfection-tolerant search tool for potential quadruplex-forming sequences in R},
    author = {Jiri Hon and Tomas Martinek and Jaroslav Zendulka and Matej Lexa},
    doi = {10.1093/bioinformatics/btx413},
    journal = {Bioinformatics},
    year = {2017},
    volume = {33},
    number = {21},
    pages = {3373-3379},
  }