To cite package ‘ef’ in publications use:

  Millar C, Fryer R, Malcolm I, Glover R (2020). _ef: Modelling
  Framework for the Estimation of Salmonid Abundance_. R package
  version 1.2.0, <https://CRAN.R-project.org/package=ef>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ef: Modelling Framework for the Estimation of Salmonid Abundance},
    author = {Colin Millar and Rob Fryer and Iain Malcolm and Ross Glover},
    year = {2020},
    note = {R package version 1.2.0},
    url = {https://CRAN.R-project.org/package=ef},
  }