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Machahn - Public Domain
Clarence Major - CC BY-SA 3.0
Public Domain
The University of Queensland - CC BY 4.0
unknown - Public Domain
work-for-hire - CC BY 3.0
Frederick William Fairholt - Public Domain
Author Unknown - Public Domain
Francis Alexander - Public Domain
unknown photographer - Public Domain
Renate Schmid, Copyright is with MFO - CC BY-SA 2.0
artist unknown - Public Domain
Alexandra Studios (Toronto): Louis or Nathan Turofsky, Roy Mitchell or Hal Crellin - Public Domain
Ianpclifford - CC BY-SA 4.0
Users :de:ArtMechanic - Public Domain
Clinedinst Studio, Washington, D.C. - Public Domain
NASA - Public Domain
Image from Wikimedia Commons
Machahn - Public Domain
Becker, Johann Philipp, 1809-1886
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Clarence Major - CC BY-SA 3.0
Major, Clarence
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Public Domain
Castor, Betty, 1941-
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Haigh, John George, 1909-1949
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The University of Queensland - CC BY 4.0
Hill, Dorothy, 1907-1997
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unknown - Public Domain
Rotch, Abbott Lawrence, 1861-1912
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work-for-hire - CC BY 3.0
Hazlitt, Henry, 1894-1993
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Ferris, Jean Leon Gerome, 1863-1930
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Frederick William Fairholt - Public Domain
Hall, S. C., Mrs., 1800-1881
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Tingey, Thomas, 1750-1829
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Author Unknown - Public Domain
Kauder, Hugo, 1888-1972
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Tiemann, Ferd. (Ferdinand), 1848-1899
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Thunberg, Carl Peter, 1743-1828
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Francis Alexander - Public Domain
Adams, Hannah, 1755-1831
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unknown photographer - Public Domain
Clift, Denison H. 1885-1961
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Suffolk, William de la Pole, Duke of, 1396-1450
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Renate Schmid, Copyright is with MFO - CC BY-SA 2.0
Lebowitz, Joel Louis, 1930-....
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artist unknown - Public Domain
Watt, G. D. (George Darling), 1812-1881
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Kluszewski, Ted, 1924-1988
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unknown - Public Domain
Weymouth, Thomas Thynne, Viscount, 1640?-1714
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Ṭūsī, Naṣīr al-Dīn Muḥammad ibn Muḥammad, 1201-1274
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Hurwicz, Leonid
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Cumberland, Henry Clifford, Earl of, 1591-1643
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Mitchell, P. (Peter), 1824-1899
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Alexandra Studios (Toronto): Louis or Nathan Turofsky, Roy Mitchell or Hal Crellin - Public Domain
Oakes, Harry, Sir, 1874-1943
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Ianpclifford - CC BY-SA 4.0
Avakian, George, 1919-2017
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Users :de:ArtMechanic - Public Domain
Lacordaire, Théodore, 1801-1870
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John Paul II, Pope, 1920-2005
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Clinedinst Studio, Washington, D.C. - Public Domain
Burns, Lucy, 1879-1966
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NASA - Public Domain
Allen, Joseph P., 1937-