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unknown - Public Domain
Charles Breijer / Anefo -
Photographer not named. - Public Domain
Unidentified photographer - Public Domain
Collyer & Hutchinson.<br/> - Public Domain
Sigma Chi Fraternity - Public Domain
WikiSysop - CC BY 2.5
US Government Printing Office (Washington, DC), publisher) - Public Domain
"The Times" (Philadelphia, PA) - Public Domain
Berridge, John and Whittingham, Richard - Public Domain
Alan Light - CC BY 2.0
JVC3ETA - Public Domain
PeteWright - CC BY 2.0
Mendelitkin - CC BY-SA 4.0
PEN American Center - CC BY 2.0
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Bordage, Pierre
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unknown - Public Domain
Kemper, James Lawson, 1823-1895
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Kyle, E. J. (Edwin Jackson), 1876-
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Nepo, Mark.
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Charles Breijer / Anefo -
Boyer, Lucienne
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Photographer not named. - Public Domain
Clayton, Powell, 1833-1914
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Brillouin, Léon, 1889-1969
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Young, Samuel Hall, 1847-1927
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Unidentified photographer - Public Domain
Ochtman, Leonard, 1854-1934.
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Renoir, Jean, 1894-1979
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Lesueur, Daniel, 1860-1921
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LeConte, John L. (John Lawrence), 1825-1883
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Alexander, Lamar, 1940-
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Ashton, Julian, 1851-1942
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Collyer & Hutchinson.<br/> - Public Domain
Trevor, Richard, 1707-1771
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Sigma Chi Fraternity - Public Domain
Meiklejohn, George D. (George de Rue), 1857-1929
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WikiSysop - CC BY 2.5
Arrian
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US Government Printing Office (Washington, DC), publisher) - Public Domain
Porter, Charles Orlando, 1919-2006
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"The Times" (Philadelphia, PA) - Public Domain
Leisenring, John, 1853-1901
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Portalis, Jean-Étienne-Marie, 1746-1807
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Berridge, John and Whittingham, Richard - Public Domain
Berridge, John, 1716-1793
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Barger, George, 1878-1939
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Leduc, Ozias
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Alan Light - CC BY 2.0
Hogarth, Burne
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Kuratowski, Kazimierz, 1896-1980
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Patch, Alexander McCarrell, 1889-1945
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JVC3ETA - Public Domain
Bográn, Luis 1849-1895
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PeteWright - CC BY 2.0
Jessop, Craig D.
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Mendelitkin - CC BY-SA 4.0
Altmann, Alexander, 1906-
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PEN American Center - CC BY 2.0
Plimpton, Martha, 1970-