To cite ferrn in publications use:

Zhang HS, Cook D, Laa U, Langrené N, Menéndez P (2021). “Visual Diagnostics for Constrained Optimisation with Application to Guided Tours.” The R Journal, 13(2), 624-641. doi:10.32614/RJ-2021-105, https://doi.org/10.32614/RJ-2021-105.

Corresponding BibTeX entry:

  @Article{,
    title = {Visual Diagnostics for Constrained Optimisation with
      Application to Guided Tours},
    author = {H. Sherry Zhang and Dianne Cook and Ursula Laa and
      Nicolas Langren{é} and Patricia Men{é}ndez},
    journal = {The R Journal},
    year = {2021},
    volume = {13},
    number = {2},
    pages = {624-641},
    url = {https://doi.org/10.32614/RJ-2021-105},
    doi = {10.32614/RJ-2021-105},
  }