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unknown - Public Domain
Evelyn de Morgan - Public Domain
unknown photographer - Public Domain
Coenraet Waumans engraver - Public Domain
United States Air Force - Public Domain
Bassano - Public Domain
Jules Pizzetta - Public Domain
Thomas Pennant - Public Domain
User at project link - Public Domain
Eugène Pirou - Public Domain
user at project - Public Domain
"Photograph courtesy of United States Steel Corporation". The company was the sponsor of the program. - Public Domain
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Castle, Nick.
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unknown - Public Domain
Salisbury, Edward Elbridge, 1814-1901
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Kim, Il-sǒng, 1912-1994
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Evelyn de Morgan - Public Domain
Spencer-Stanhope, Roddam, 1829-1908
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Hale, Horatio, 1817-1896
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Beauharnais, Eugène de, 1781-1824
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Eichberg, Julius, 1824-1893
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Tucker, George, 1775-1861
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Eberle, Edward W. (Edward Walter), 1864-1929
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unknown photographer - Public Domain
Iradier Bulfi, Manuel, 1854-1911
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Hammersley, W. J. (William Josiah), 1826-1886
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Coenraet Waumans engraver - Public Domain
Saftleven, Herman, 1609-1685
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Templeton, Robert
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Špála, Václav
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United States Air Force - Public Domain
Voll, John James, 1922-1987
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unknown - Public Domain
Michelena, Beatriz, 1890-1942
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Allioni, Carlo, 1725-1804
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unknown - Public Domain
Willet, Andrew, 1562-1621
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Bassano - Public Domain
Grey of Fallodon, Edward Grey, Viscount, 1862-1933
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Jules Pizzetta - Public Domain
Brongniart, Alexandre, 1770-1847
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Thomas Pennant - Public Domain
South, Robert, 1634-1716
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Pingret, Édouard (1788-1875).
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User at project link - Public Domain
Stander, Lionel
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Robertson, Frederick William, 1816-1853
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Jourdan, Émile, 1860-1931
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Barrios de Chamorro, Violeta
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Eugène Pirou - Public Domain
Cherbuliez, Victor, 1829-1899
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Ross, Shirley, 1913-1975
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user at project - Public Domain
Davern, Kenny
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"Photograph courtesy of United States Steel Corporation". The company was the sponsor of the program. - Public Domain
Kiley, Richard