A sources

A-grade sources are strong tier-1 citation targets. They meet the bar across all three dimensions — Discipline, Modern Reference, and Velocity — but typically have one signal slightly behind A+ peers (e.g., paywalled access reducing Modern Reference, or younger publication date reducing Velocity).

A sources, ranked

1. #1
   Wikipedia (English)

   en.wikipedia.org · Reference
   A·94
2. #2
   PubMed

   pubmed.ncbi.nlm.nih.gov · Academic
   A·94
3. #3
   U.S. Census Bureau

   census.gov · Government
   A·94
4. #4
   U.S. Bureau of Labor Statistics

   bls.gov · Government
   A·94
5. #5
   U.S. Food and Drug Administration

   fda.gov · Government
   A·94
6. #6
   U.S. Centers for Disease Control and Prevention

   cdc.gov · Government
   A·94
7. #7
   U.S. National Oceanic and Atmospheric Administration

   noaa.gov · Government
   A·93
8. #8
   European Central Bank

   ecb.europa.eu · Government
   A·93
9. #9
   NASA

   nasa.gov · Government
   A·93
10. #10
    MDN Web Docs

    developer.mozilla.org · Reference
    A·93
11. #11
    European Commission

    ec.europa.eu · Government
    A·92
12. #12
    Bank of England

    bankofengland.co.uk · Government
    A·92
13. #13
    U.S. Energy Information Administration

    eia.gov · Government
    A·92
14. #14
    CERN

    home.cern · Academic
    A·92
15. #15
    PNAS

    pnas.org · Academic
    A·92
16. #16
    European Medicines Agency

    ema.europa.eu · Government
    A·91
17. #17
    U.S. Patent and Trademark Office

    uspto.gov · Government
    A·91
18. #18
    U.S. Department of Agriculture

    usda.gov · Government
    A·91
19. #19
    U.S. Geological Survey

    usgs.gov · Government
    A·91
20. #20
    OECD

    oecd.org · Government
    A·91
21. #21
    FRED (Federal Reserve Economic Data)

    fred.stlouisfed.org · Government
    A·91
22. #22
    IPCC

    ipcc.ch · Government
    A·91
23. #23
    Reuters

    reuters.com · News
    A·89
24. #24
    arXiv

    arxiv.org · Academic
    A·89
25. #25
    World Health Organization

    who.int · Government
    A·89
26. #26
    World Trade Organization

    wto.org · Government
    A·89
27. #27
    Cell

    cell.com · Academic
    A·89
28. #28
    Stanford Encyclopedia of Philosophy

    plato.stanford.edu · Reference
    A·89
29. #29
    The New York Times

    nytimes.com · News
    A·88
30. #30
    World Bank

    worldbank.org · Government
    A·88
31. #31
    Eurostat

    ec.europa.eu/eurostat · Government
    A·88
32. #32
    Nature

    nature.com · Academic
    A·87
33. #33
    New England Journal of Medicine

    nejm.org · Health
    A·87
34. #34
    Cochrane Library

    cochranelibrary.com · Academic
    A·87
35. #35
    ONS (UK)

    ons.gov.uk · Government
    A·87
36. #36
    Mayo Clinic

    mayoclinic.org · Health
    A·87
37. #37
    Associated Press

    apnews.com · News
    A·86
38. #38
    ProPublica

    propublica.org · News
    A·86
39. #39
    Science

    science.org · Academic
    A·86
40. #40
    The Lancet

    thelancet.com · Health
    A·86
41. #41
    The Washington Post

    washingtonpost.com · News
    A·86
42. #42
    Our World in Data

    ourworldindata.org · Research
    A·86
43. #43
    International Monetary Fund

    imf.org · Government
    A·86
44. #44
    Journal of the American Medical Association

    jamanetwork.com · Health
    A·86
45. #45
    UNESCO

    en.unesco.org · Government
    A·86
46. #46
    European Space Agency

    esa.int · Government
    A·86
47. #47
    BEA

    bea.gov · Government
    A·86
48. #48
    The Guardian

    theguardian.com · News
    A·85
49. #49
    Encyclopædia Britannica

    britannica.com · Reference
    A·85
50. #50
    The Wall Street Journal

    wsj.com · News
    A·85
51. #51
    Pew Research Center

    pewresearch.org · Research
    A·85
52. #52
    The BMJ (British Medical Journal)

    bmj.com · Health
    A·85
53. #53
    National Bureau of Economic Research

    nber.org · Academic
    A·85
54. #54
    Quanta Magazine

    quantamagazine.org · Magazine
    A·85
55. #55
    Association for Computing Machinery

    dl.acm.org · Academic
    A·85