To cite the cordillera package in publications use:

Rusch T, Hornik K, Mair P (2018). “Assessing and quantifying clusteredness: The OPTICS Cordillera.” Journal of Computational and Graphical Statistics, 27(1), 220-233. doi:10.1080/10618600.2017.1349664.

Corresponding BibTeX entry:

  @Article{,
    author = {Thomas Rusch and Kurt Hornik and Patrick Mair},
    title = {Assessing and quantifying clusteredness: The {OPTICS}
      {C}ordillera},
    journal = {Journal of Computational and Graphical Statistics},
    number = {1},
    volume = {27},
    pages = {220-233},
    year = {2018},
    doi = {10.1080/10618600.2017.1349664},
  }