From the Crossref Blog:
The Crossref graph of the research enterprise is growing at an impressive rate of 2.5 million records a month – scholarly communications of all stripes and sizes. Preprints are one of the fastest growing types of content.
While preprints may not be new, the growth may well be: ~30% for the past 2 years (compared to article growth of 2-3% for the same period). We began supporting preprints in November 2016 at the behest of our members. When members register them, we ensure that: links to these publications persist over time; they are connected to the full history of the shared research results; and the citation record is clear and up-to-date.
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