To cite fechner in publications use:

Ünlü A, Kiefer T, Dzhafarov EN (2009). “Fechnerian Scaling in R: The Package fechner.” Journal of Statistical Software, 31(6), 1–24. https://www.jstatsoft.org/article/view/v031i06.

Corresponding BibTeX entry:

  @Article{,
    title = {Fechnerian Scaling in {R}: The Package {fechner}},
    author = {Ali \"Unl\"u and Thomas Kiefer and Ehtibar N. Dzhafarov},
    journal = {Journal of Statistical Software},
    year = {2009},
    volume = {31},
    number = {6},
    pages = {1--24},
    url = {https://www.jstatsoft.org/article/view/v031i06},
  }