| - C: History: Auxiliary sciences
- CB: History of Civilization
- CC: Archaeology
- CD: Diplomatics, Archives, Seals
- CE: Technical chronology; Calendars
- CJ: Numismatics
- CN: Inscriptions, Epigraphy
- CR: Heraldry
- CS: Genealogy
- CT: Biography (General)
- D: History: General, and Regions Outside the Americas
- DA: Great Britain and Ireland
- DAW: Central Europe
- DB: Austria, Hungary, Czech Republic, Slovakia
- DC: France, Andorra, Monaco
- DD: Germany
- DE: Mediterreanean Region, Greco-Roman World
- DF: Greece
- DG: Italy
- DH-DJ: Belgium, Luxembourg, Netherlands
- DH: Low Countries (General), Belgium, Luxembourg
- DJ: The Netherlands
- DJK: Eastern Europe
- DK: Russia, Former Soviet Republics, Poland
- DL: Northern Europe, Scandinavia
- DP: Spain, Portugal
- DQ: Switzerland
- DR: Balkan Region
- DS: Asia
- DT: Africa
- DU: Oceania, Australia, New Zealand
- DX: Romanies
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