To cite equate in publications use:

Anthony D. Albano (2016). equate: An R Package for Observed-Score Linking and Equating. Journal of Statistical Software, 74(8), 1-36.<doi:10.18637/jss.v074.i08>

Corresponding BibTeX entry:

  @Article{,
    title = {{equate}: An {R} Package for Observed-Score Linking and
      Equating},
    author = {Anthony D. Albano},
    journal = {Journal of Statistical Software},
    year = {2016},
    volume = {74},
    number = {8},
    pages = {1--36},
    doi = {10.18637/jss.v074.i08},
  }