Columbia subject headings:
Harvard subject headings:
Chronology, Historical
History, Modern, in art.
History, Modern--20th century
History, Modern--21st century
Photography in historiography
Pictures as information resources.
Princeton subject headings:
Chronology, Historical.
History, Modern, in art.
History, Modern--20th century.
History, Modern--21st century.
Photography in historiography.
Pictures as information resources.