To cite CircMLE in publications use Fitak and Johnsen 2017. If using the HR test or Pycke test, please also cite Landler et al. 2019:

Fitak, R. R. and Johnsen, S. (2017). Bringing the analysis of animal orientation data full circle: model-based approaches with maximum likelihood. Journal of Experimental Biology, 220, 3878-3882.<doi:10.1242/jeb.167056>

Landler, L., Ruxton, G. D., and Malkemper, E. P. (2019). The Hermans–Rasson test as a powerful alternative to the Rayleigh test for circular statistics in biology. BMC Ecology, 19, 30.<doi:10.1186/s12898-019-0246-8>

Corresponding BibTeX entries:

  @Article{,
    title = {Bringing the analysis of animal orientation data full
      circle: model-based approaches with maximum likelihood},
    author = {Robert R. Fitak and Sonke Johnsen},
    journal = {Journal of Experimental Biology},
    year = {2017},
    volume = {220},
    number = {3},
    pages = {3878-3882},
    url = {https://doi.org/10.1242/jeb.167056},
  }

  @Article{,
    title = {The Hermans–Rasson test as a powerful alternative to the
      Rayleigh test for circular statistics in biology},
    author = {Lukas Landler and Graeme D. Ruxton and E. Pascal
      Malkemper},
    journal = {BMC Ecology},
    year = {2019},
    volume = {19},
    pages = {30},
    url = {https://doi.org/10.1186/s12898-019-0246-8},
  }