{{Cite| last1 = Barnier| first1 = Julien| last2 = Briatte| first2 = François| last3 = Larmarange| first3 = Joseph| title = questionr: Functions to Make Surveys Processing Easier| access-date = 2021-12-21| date = 2021-10-06| url = https://CRAN.R-project.org/package=questionr}}