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Elena Torre - CC BY-SA 2.0
Peter Hummers - CC BY-SA 2.0
Public Domain
US gov - Public Domain
USMC - Public Domain
Eva Rinaldi - CC BY-SA 2.0
artwork drawn by Adolph Boÿ, engraved by Jeremias Falck - Public Domain
Karl Schumacher -
G. Koopmans (Phillip Hillion: "I give you the permission because they are public. Only condition, no trade.") - CC BY-SA 3.0
w:White House Photographic Office -
unknown - Public Domain
Dulce Osuna -
Whoisjohngalt - CC BY-SA 3.0
original uploader - CC BY 2.5
Blaues Sofa - CC BY 2.0
anonymous -
Flickr user Randalfino - CC BY 2.0
Harney McCaffery Collection -
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Richer, Jean
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Elena Torre - CC BY-SA 2.0
Hopkins, Anthony, 1937-....
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Sassetta, approximately 1400-1450
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Liebknecht, Karl Paul August Friedrich, 1871-1919
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Peter Hummers - CC BY-SA 2.0
Schickele, Peter
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Barrow, Edward Grant, 1868-1953
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Public Domain
Hawley, James H. (James Henry), 1847-1929
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Saint-Georges, Joseph Bologne, chevalier de, 1745-1799
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Mayer, Jean, 1920-
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US gov - Public Domain
Polanco Abreu, Santiago, 1920-1988
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USMC - Public Domain
Holcomb, Thomas, 1879-1965
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Eva Rinaldi - CC BY-SA 2.0
Connolly, Billy
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Blommers, B.J. (Bernardus Johannes), 1845-1914
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Sabinus, Georg, 1508-1560
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artwork drawn by Adolph Boÿ, engraved by Jeremias Falck - Public Domain
Alhazen, 965-1039
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Karl Schumacher -
Porter, Roger B.
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G. Koopmans (Phillip Hillion: "I give you the permission because they are public. Only condition, no trade.") - CC BY-SA 3.0
Prigogine, I. (Ilya)
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w:White House Photographic Office -
Crosland, Anthony, 1918-1977
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unknown - Public Domain
Lincoln, Enoch, 1788-1829
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Dulce Osuna -
Graham, Katerina, 1989-
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Whoisjohngalt - CC BY-SA 3.0
Whitehead, John C., 1922-....
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original uploader - CC BY 2.5
Bear, Greg, 1951-....
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Blaues Sofa - CC BY 2.0
Albahari, David, 1948-....
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Ye, Jianying
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Public Domain
Arlosoroff, Chaim, 1899-1933
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anonymous -
Schleich, Carl Ludwig, 1859-1922
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Westcott, Brooke Foss, 1825-1901
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unknown - Public Domain
Kawanabe, Gyōsai, 1831-1889
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Flickr user Randalfino - CC BY 2.0
Aubert, Jean-Louis, 1955-....
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Harney McCaffery Collection -
Harney, W. E. (William Edward), 1895-1962