To cite the rpanel package in publications use:

Bowman A, Crawford E, Alexander G, Bowman RW (2007). “rpanel: Simple Interactive Controls for R Functions Using the tcltk Package.” Journal of Statistical Software, 17(9), 1–18. https://www.jstatsoft.org/v17/i09/.

To cite rpanel's spatial teaching tools (rp.geosim, rp.mururoa, rp.firth) use:

Bowman AW, Gibson I, Scott EM, Crawford E (2010). “Interactive Teaching Tools for Spatial Sampling.” Journal of Statistical Software, 36(13), 1–17. https://www.jstatsoft.org/v36/i13/.

Corresponding BibTeX entries:

  @Article{,
    title = {{rpanel}: Simple Interactive Controls for {R} Functions
      Using the {tcltk} Package},
    author = {Adrian Bowman and Ewan Crawford and Gavin Alexander and
      Richard W. Bowman},
    journal = {Journal of Statistical Software},
    year = {2007},
    volume = {17},
    number = {9},
    pages = {1--18},
    url = {https://www.jstatsoft.org/v17/i09/},
  }

  @Article{,
    title = {Interactive Teaching Tools for Spatial Sampling},
    author = {Adrian W. Bowman and Iain Gibson and E. Marian Scott and
      Ewan Crawford},
    journal = {Journal of Statistical Software},
    year = {2010},
    volume = {36},
    number = {13},
    pages = {1--17},
    url = {https://www.jstatsoft.org/v36/i13/},
  }