Best paywall-free sources for citation by Citation Discipline

Same 15 sources, re-sorted by Citation Discipline only — different signal than the composite Index. The leader changes: U.S. Securities and Exchange Commission takes the top position at A+ · 98.

1. 1
   U.S. Securities and Exchange Commissionsec.gov↑1

   Primary-source regulator publishing every public-company filing (13F, 10-K, 8-K, etc.) since 1934.

   Discipline A+ · 98·Index A+ · 96·Government
   A+·98
2. 2
   Federal Reserve Systemfederalreserve.gov↑5

   U.S. central bank; primary source for monetary policy + economic data + financial-system statistics.

   Discipline A+ · 96·Index A+ · 95·Government
   A+·96
3. 3
   Wikipedia (English)en.wikipedia.org↑8

   Crowd-edited encyclopedia with ~7M articles and per-article inline citation discipline.

   Discipline A+ · 96·Index A · 94·Reference
   A+·96
4. 4
   PubMedpubmed.ncbi.nlm.nih.gov↑8

   U.S. National Library of Medicine literature index covering ~36M biomedical citations.

   Discipline A+ · 96·Index A · 94·Academic
   A+·96
5. 5
   U.S. Food and Drug Administrationfda.gov↑9

   Federal agency for food + drug + medical-device safety; primary-source approvals + safety alerts.

   Discipline A+ · 96·Index A · 94·Government
   A+·96
6. 6
   U.S. National Institutes of Healthnih.gov↓1

   U.S. federal medical research agency operating PubMed, NCBI, MedlinePlus, and trial registries.

   Discipline A+ · 95·Index A+ · 95·Government
   A+·95
7. 7
   U.S. Census Bureaucensus.gov↓1

   Federal statistical agency for U.S. demographic + economic data; primary-source decennial census + ACS surveys.

   Discipline A+ · 95·Index A · 94·Government
   A+·95
8. 8
   U.S. Bureau of Labor Statisticsbls.gov↑1

   Federal statistical agency for U.S. labor + price data; CPI, employment, unemployment, productivity.

   Discipline A+ · 95·Index A · 94·Government
   A+·95
9. 9
   U.S. Centers for Disease Control and Preventioncdc.gov↑1

   Federal agency for U.S. public-health surveillance + disease prevention; primary-source MMWR + WONDER data.

   Discipline A+ · 95·Index A · 94·Government
   A+·95
10. 10
    U.S. National Oceanic and Atmospheric Administrationnoaa.gov↑5

    Federal scientific agency for weather + ocean + climate data; primary-source forecasts + climate research.

    Discipline A+ · 95·Index A · 93·Government
    A+·95
11. 11
    NASAnasa.gov↓3

    U.S. space agency; primary source for space exploration + Earth science + aeronautics research.

    Discipline A · 94·Index A · 93·Government
    A·94
12. 12
    DOI (CrossRef Resolver)doi.org↓11

    International standard identifier resolver for academic citations (~150M+ DOIs).

    Discipline A · 92·Index A+ · 95·Academic
    A·92
13. 13
    MDN Web Docsdeveloper.mozilla.org↓9

    Mozilla-stewarded web-platform reference since 2005; default citation for HTML, CSS, JS, Web APIs.

    Discipline A · 92·Index A · 93·Reference
    A·92
14. 14
    Semantic Scholarsemanticscholar.org↓1

    AI-powered academic search engine by Allen Institute for AI; ~200M+ papers indexed.

    Discipline A · 86·Index B · 83·Academic
    A·86
15. 15
    arXivarxiv.org↓12

    Open-access preprint server for physics, mathematics, computer science; ~2.4M papers since 1991.

    Discipline B · 78·Index A · 89·Academic
    B·78