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unknown - Public Domain
FabioSciortino - CC BY-SA 4.0
Bain News Service - Public Domain
Radio Daily - Public Domain
"The Times" (Philadelphia, PA) - Public Domain
A. C. Cooper - Public Domain
USMC - Public Domain
self-scanned; photographer unknown - Public Domain
Rob Bogaerts / Anefo -
James Pardon - Public Domain
Mikkel Bosch Jacobsen-Jean Conttraux-Didier Pleux-Jacques Van Rillaer-Cattherine Meyer-Año 2005 - Public Domain
Airaschen - CC BY-SA 4.0
Xanathon - CC BY-SA 3.0
J. I. Gutierrez - Public Domain
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Vollmer, August, 1876-1955
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Sonnevi, Göran, 1939-
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Jernigan, Tamara Elizabeth, 1959-
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Mendes, Chico, -1988
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unknown - Public Domain
Baillarger, Jules Gabriel François, 1809-1890
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FabioSciortino - CC BY-SA 4.0
Lo Verso, Enrico
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Bain News Service - Public Domain
Gibbs, George, 1870-1942
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Waldmeier, Theophilus, 1832-1915
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Radio Daily - Public Domain
Smith, Wonderful
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"The Times" (Philadelphia, PA) - Public Domain
Leisenring, John, 1853-1901
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Watson, Thomas, 1557?-1592?
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A. C. Cooper - Public Domain
Boys, C.V. (Charles Vernon), 1855-1944
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USMC - Public Domain
Barrow, Robert H.
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Pólya, George, 1887-1985
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self-scanned; photographer unknown - Public Domain
Grenet, Eliseo, 1893-1950
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unknown - Public Domain
O'Shea, Milo, 1926-2013
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Rob Bogaerts / Anefo -
Paulos Gregorios, 1922-
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James Pardon - Public Domain
Darwin, Robert Waring, 1766-1848
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Mikkel Bosch Jacobsen-Jean Conttraux-Didier Pleux-Jacques Van Rillaer-Cattherine Meyer-Año 2005 - Public Domain
Schreber, Daniel Paul, 1842-1911
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Heinlein, Robert A. (Robert Anson), 1907-1988
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Adkins, Scott, 1976-....
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Rosslyn, Alexander Wedderburn, Earl of, 1733-1805
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Airaschen - CC BY-SA 4.0
Elías, Manuel de 1939-
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Raines, Ella, 1921-1988
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Xanathon - CC BY-SA 3.0
McDiarmid, Ian 1944-
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Sutherland, Jane, 1855-1928
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Wallach, Otto, 1847-1931
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J. I. Gutierrez - Public Domain
Pombo, Rafael, 1833-1912
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unknown - Public Domain
Snyder, C. B. J., 1860-1945
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Rossellino, Antonio, 1427-1479