To cite the 'multimark' package in publications use:

McClintock BT (2015). “multimark: an R package for analysis of capture-recapture data consisting of multiple “noninvasive” marks.” Ecology and Evolution, 5(21), 4920-4931. https://doi.org/10.1002/ece3.1676.

McClintock B (2021). multimark: capture-mark-recapture analysis using multiple non-invasive marks. R package version 2.1.3.

Corresponding BibTeX entries:

  @Article{,
    title = {multimark: an R package for analysis of capture-recapture
      data consisting of multiple ``noninvasive'' marks},
    author = {B. T. McClintock},
    year = {2015},
    journal = {Ecology and Evolution},
    volume = {5},
    number = {21},
    pages = {4920-4931},
    url = {https://doi.org/10.1002/ece3.1676},
  }
  @Manual{,
    title = {multimark: capture-mark-recapture analysis using multiple
      non-invasive marks},
    author = {Brett McClintock},
    year = {2021},
    note = {R package version 2.1.3},
  }