To cite nparLD in publications use:

Noguchi K, Gel YR, Brunner E, Konietschke F (2012). “nparLD: An R Software Package for the Nonparametric Analysis of Longitudinal Data in Factorial Experiments.” Journal of Statistical Software, 50(12), 1–23. https://www.jstatsoft.org/v50/i12/.

Corresponding BibTeX entry:

  @Article{,
    title = {{nparLD}: An {R} Software Package for the Nonparametric
      Analysis of Longitudinal Data in Factorial Experiments},
    author = {Kimihiro Noguchi and Yulia R. Gel and Edgar Brunner and
      Frank Konietschke},
    journal = {Journal of Statistical Software},
    year = {2012},
    volume = {50},
    number = {12},
    pages = {1--23},
    url = {https://www.jstatsoft.org/v50/i12/},
  }