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 RR, Johnsen S (2017). “Bringing the analysis of animal orientation data full circle: model-based approaches with maximum likelihood.” Journal of Experimental Biology, 220(3), 3878-3882. https://doi.org/10.1242/jeb.167056.

Landler L, Ruxton GD, Malkemper EP (2019). “The Hermans–Rasson test as a powerful alternative to the Rayleigh test for circular statistics in biology.” BMC Ecology, 19, 30. https://doi.org/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},
  }