Since 1st January 2018, Crossref has had a new reference distribution policy, described at https://www.crossref.org/reference-distribution/. There are three possible options for setting the reference distribution preference from which a publisher can choose, these being ‘Closed’, ‘Limited’ and ’Open“. If the ‘Closed’ option is chosen, the references will only be used for the Crossref Cited-by service, and are not distributed via any of the