To cite unmarked in publications use:

Kellner KF, Smith AD, Royle JA, Kery M, Belant JL, Chandler RB (2023). “The unmarked R package: Twelve years of advances in occurrence and abundance modelling in ecology.” Methods in Ecology and Evolution, 14(6), 1408–1415. https://www.jstatsoft.org/v43/i10/.

Fiske I, Chandler R (2011). “unmarked: An R Package for Fitting Hierarchical Models of Wildlife Occurrence and Abundance.” Journal of Statistical Software, 43(10), 1–23. https://www.jstatsoft.org/v43/i10/.

Corresponding BibTeX entries:

  @Article{,
    title = {The {unmarked} {R} package: Twelve years of advances in
      occurrence and abundance modelling in ecology},
    author = {Kenneth F. Kellner and Adam D. Smith and J. Andrew Royle
      and Marc Kery and Jerrold L. Belant and Richard B. Chandler},
    journal = {Methods in Ecology and Evolution},
    year = {2023},
    volume = {14},
    number = {6},
    pages = {1408--1415},
    url = {https://www.jstatsoft.org/v43/i10/},
  }

  @Article{,
    title = {{unmarked}: An {R} Package for Fitting Hierarchical Models
      of Wildlife Occurrence and Abundance},
    author = {Ian Fiske and Richard Chandler},
    journal = {Journal of Statistical Software},
    year = {2011},
    volume = {43},
    number = {10},
    pages = {1--23},
    url = {https://www.jstatsoft.org/v43/i10/},
  }