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unknown - Public Domain
Liona Boyd (rights-holder) / Keith Williamson (photographer) - CC BY-SA 3.0
Self-portrait - CC BY-SA 3.0
B. Braquehais - Public Domain
Not specified, owned by :en:John F. Kennedy Presidential Library and Museum - Public Domain
user at project - Public Domain
Public Domain
Mike Cline - Public Domain
NASA - Public Domain
Slowking4 -
gdcgraphics - CC BY-SA 2.0
MOSSOT - CC BY-SA 3.0
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Fletcher, Horace, 1849-1919
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unknown - Public Domain
Pinkham, Lydia Estes, 1819-1883
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Wright, Milton, 1828-1917
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Liona Boyd (rights-holder) / Keith Williamson (photographer) - CC BY-SA 3.0
Boyd, Liona
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Khomi︠a︡kov, A. S. (Alekseĭ Stepanovich), 1804-1860
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Maish, Levi, 1837-1899
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Waddell, Rube, 1876-1914
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Wellman, Walter, 1858-1934
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Self-portrait - CC BY-SA 3.0
Kohn, Alfie.
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Hale, Philip Leslie, 1865-1931
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Tuwim, Julian, 1894-1953
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B. Braquehais - Public Domain
Saint-Léon, Arthur, 1821-1870
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Clarke, Reader W. (Reader Wright), 1812-1872
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Not specified, owned by :en:John F. Kennedy Presidential Library and Museum - Public Domain
Hemingway, Patrick.
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White, Hugh Lawson, 1773-1840
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Goodnight, Isaac Herschel, 1849-1901
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user at project - Public Domain
Brereton, Joseph Lloyd, 1822-1901
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Arsonval, Jacques Arséne d', (1851-1940)
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Kalloch, Isaac, 1831-1887
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Public Domain
Dalton, Tristram, 1738-1817
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Mike Cline - Public Domain
Bozeman, John, 1835-1867
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NASA - Public Domain
United States. National Aeronautics and Space Administration
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McKinlay, John, 1819-1872
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Slowking4 -
Gantos, Jack.
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gdcgraphics - CC BY-SA 2.0
Richardson, Joely
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unknown - Public Domain
Zarncke, Friedrich, 1825-1891
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Stefanyk, Vasylʹ Semenovych, 1871-1936
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Heaton, J. Henniker
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Rutherford, William, 1839-1899
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MOSSOT - CC BY-SA 3.0
Brusset, Jean-Paul 1909-1985