Requirements for citations to be treated as First-Class Data Entities In my introductory blog post, I listed five requirements for the treatment of citations as first-class data entities.  The first of these requirements is that they must be definable in a machine-readable manner as a member of the class “Citation”, and describable using appropriate ontology terms.

Citations are now centre stage As a result of the Initiative for Open Citations (I4OC), launched on April 6 last year, almost all the major scholarly publishers now open the reference lists they submit to Crossref, resulting in more than half a billion references being openly available via the Crossref API.

Some folk are confused, but OpenCitations and the Initiative for Open Citations, despite the similarity of their names, are two distinct organizations.

Good news!  Today, on January 16th 2018, Oxford University Press (OUP) announced its participation in the Initiative for Open Citations, and requested Crossref to turn on reference sharing for all OUP deposited references from more than half a million publications.  Oxford University Press is the largest university press in the world, publishing in 70 languages and 190 countries.

On 9th January 2018, I published a World View article in Nature entitled ***Funders should mandate open citations ***[1], in which I argue that access to open references from scholarly publications is so important that, when encouragements from organisations such as the Initiative for Open Citations (I4OC) to publishers to open their references fall on deaf ears, then sterner measures are required.

Two significant barriers prevent comprehensive reference availability through Crossref. The first barrier First, two-thirds of Crossref’s publisher-members, in particular the smaller ones, do not submit references along with the other details of their publications. Many of these published works are of types (e.g. abstracts, editorials and news items) that lack any references.

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

For completeness, this post, also based on analyses performed by Daniel Ecer of eLife (<d.ecer@elifesciences.org)> on data he downloaded from Crossref in September 2017 (Ecer, 2017), complements the two preceding posts, and details the openness of references from scholarly publishers other than Elsevier.

Yesterday (November 23rd 2017) I was working with Daniel Ecer of eLife (<d.ecer@elifesciences.org)> to dig some hard facts out of the analyses he undertook on data he downloaded from Crossref in September 2017 (Ecer, 2017).  Because of its dominant position in the scholarly publishing world, in this, the second of two related posts, I report the results for references from works published by Elsevier.

Yesterday (November 23rd 2017) I was working with Daniel Ecer of eLife (<d.ecer@elifesciences.org)> to dig some hard facts out of the analyses he undertook on data he downloaded from Crossref in September 2017 (Ecer, 2017).  In this, the first of two related posts, I report the results for all publishers . **The analyses show that, of the 33,672,763 journal articles documented in Crossref that have accompanying