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References

The encyclopedia cites 28,668 distinct works across 38,352 citations. Every citation was checked to exist and to support the specific claim it sits on.

A further 737 entries have been withdrawn — works the audit could not find in any authority, and inline prose definitions our extractor had stored as though they were sources. Their pages remain and say why; they are excluded from every count below.

Coverage, stated plainly

Reference density is very uneven across the four catalogs. That is worth saying outright rather than hiding behind a single total:

CatalogArtifactsWith referencesCoverageCitations
Primes1,4821,41595%15,512
Domain-specific7,5566,44085%20,502
Solution archetypes not yet referenced1,10600%0
Mechanisms9,8582,31523%2,338

Two of the four catalogs carry essentially no references today. That is a real gap, not a rounding error, and it is stated here rather than averaged away into a single headline number.

What is being cited

Kind of source

Whether a claim rests on the study that produced a result or on somebody's summary of it is the single most useful thing to know about a bibliography, so it is the first thing shown here.

Kind of sourceWorksShare%
Primary sourcesWhere a result was first reported — the paper, experiment, dataset, or standard itself.8,13328.4%
Secondary sourcesWork that synthesises or teaches rather than reports: reviews, monographs, textbooks, reference works.10,27835.9%
Review or monograph7,71126.9%
Textbook1,6405.7%
Reference work9273.2%
Grey and web sourcesOutside the formal literature — working papers, institutional reports, web pages.2,4758.6%
Grey literature1,0123.5%
Web1,4635.1%
UnclassifiedThe citation is too thin to classify from. Counted here rather than quietly dropped.7,78227.1%

A link's destination is a rough proxy for how durable it is. A DOI resolves for as long as the registrar exists; a publisher's marketing page does not. Grouped by kind of target rather than by hostname, so the long tail of individual publisher domains does not drown the shape.

TargetWorksShare%
DOI (doi.org)11,92041.6%
Other web3,41211.9%
Open Library9873.4%
Internet Archive9623.4%
Government / official5571.9%
University presses4381.5%
Publishers3951.4%
Standards bodies2680.9%
Wikipedia2320.8%
arXiv1430.5%
PubMed / NCBI1290.4%
JSTOR1210.4%
Google Books / search770.3%
WorldCat360.1%
Project Gutenberg300.1%
No link yet8,96131.3%

19,707 of the 28,668 works (69%) carry a link; 8,961 do not yet. Nothing is hidden — filter the browse table by link status to see exactly which.

Who published the work

Every work with a DOI has a registrant, and the concentration is worth stating: this is the substrate the encyclopedia's citable literature sits on. Attributed from the Crossref record where we hold one, and otherwise from the DOI prefix, which belongs to the registrant.

PublisherWorksShare%
Springer Nature1,88015.8%
Elsevier1,53713.0%
Wiley9217.8%
Cambridge University Press6105.1%
Oxford University Press5394.5%
JSTOR4884.1%
Taylor & Francis4764.0%
American Physical Society3462.9%
Institute of Electrical and Electronics Engineers3462.9%
American Psychological Association3412.9%
Association for Computing Machinery3392.9%
SAGE3242.7%
University of Chicago Press1981.7%
American Mathematical Society1871.6%
276 more publishers3,33528.1%

This covers the 11,867 works with a DOI, not the whole registry — 16,801 works are cited without one. Publisher names are as Crossref reports them, rolled up where one publisher arrives under several spellings.