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Bertha Howell - Public Domain
unknown - Public Domain
AgnosticPreachersKid - CC BY-SA 3.0
Public Domain
unknown - CC0 1.0
unknown photographer - Public Domain
עדי כהן צדק - CC BY-SA 3.0
author - Public Domain
Macfadden Publications - Public Domain
supercraigtalbert - CC BY 2.0
Jan Vilímek - Public Domain
Photo by Barraud, Scan by Steven J Plunkett from private copy of book - Public Domain
Sgerbic - CC BY-SA 3.0
Hans Holzer - Public Domain
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Munro, Neil Gordon, 1863-1942
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Bertha Howell - Public Domain
Jones, Mother, 1837-1930
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unknown - Public Domain
Edgerton, Sidney, 1818-1900
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AgnosticPreachersKid - CC BY-SA 3.0
American Red Cross
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Kelly, George, 1887-1974
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Public Domain
Dudley, Charles Edward, 1780-1841
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unknown - CC0 1.0
Balodis, Jānis, 1881-1965
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unknown - Public Domain
Hornbostel, Henry, 1867-1961
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Newton, Isaac, 1642-1727
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unknown photographer - Public Domain
Grundén, Per 1922-2011
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עדי כהן צדק - CC BY-SA 3.0
Duchin, Arkadi, 1963-
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unknown - Public Domain
Wilson, Edmund B. (Edmund Beecher), 1856-1939
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author - Public Domain
Battle, Cullen A. (Cullen Andrews), 1829-1905
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Macfadden Publications - Public Domain
Block, Martin, 1903-1967
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Adams, Art, 1963-
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supercraigtalbert - CC BY 2.0
Richthofen Castle (Denver, Colo.)
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Taft, Henry W. (Henry Waters), 1859-1945
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Jan Vilímek - Public Domain
Zeyer, Julius, 1841-1901
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Photo by Barraud, Scan by Steven J Plunkett from private copy of book - Public Domain
Reeves, Sims, 1818-1900
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Sgerbic - CC BY-SA 3.0
Carroll, Robert Todd, 1945-
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author - Public Domain
Wetherall, George
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Richter, Franz Xaver, 1709-1789
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Rayer, Pierre-François-Olive, 1793-1867
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Warre, Edmond, 1837-1920
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Ban, Gu, 32-92
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Gabriel de Borbón, Infante of Spain, 1752-1788
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Galbraith, Barry
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Hans Holzer - Public Domain
Holzer, Hans, 1920-2009
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Blankenhorn, Herbert, 1906-
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Stout, Robert, 1844-1930