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CHRISTOPHER MACSURAK - CC BY 2.0
Erling Mandelmann - CC BY-SA 3.0
anonymous - Public Domain
Thomas Murray - Public Domain
unknown - Public Domain
John F. Kennedy Presidential Library, National Archives - Public Domain
Richard Lewinsohn - Public Domain
luca.ghedini@gmail.com - CC BY-SA 2.5
Neozoon - CC0 1.0
USNHC - Public Domain
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Valstad, Otto
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Jones, J.A. (Jonathan A.)
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Alley, R. W., 1955-
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Thatcher, Samuel, 1776-1872
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Leonardo, da Vinci, 1452-1519
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Perraud, Adolphe
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Doyle, Francis Hastings, Sir, 1810-1888
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Liang, Sicheng, 1901-1972
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Frelinghuysen, Theodorus Jacobus, approximately 1691-approximately 1747
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Meĭerkholʹd, V. Ė. (Vsevolod Ėmilʹevich), 1874-1940
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Hampden, John, 1594-1643
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Companys y Jover, Luis, 1882-1940
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Labriola, Antonio, 1843-1904
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Travers, P.L. (Pamela Lyndon), 1899-1996
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Loris-Melikov, Mikhail Tarīelovich, graf, 1825-1888
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CHRISTOPHER MACSURAK - CC BY 2.0
Miele, Carlos
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Erling Mandelmann - CC BY-SA 3.0
Dreyer, Carl Theodor, 1889-1968
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anonymous - Public Domain
Valdés, Fernando de, 1483-1568
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Thomas Murray - Public Domain
Halley, Edmond, 1656-1742
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unknown - Public Domain
Lassell, W. (William), 1799-1880
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Hutchison, Ralph Cooper, 1898-1966
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Robin, Charles, 1743?-1824
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Heckel, Erich, 1883-1970
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John F. Kennedy Presidential Library, National Archives - Public Domain
Warnecke, John Carl
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Weyr, Eduard, 1852-1903
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Richard Lewinsohn - Public Domain
Hanussen, Erik Jan, 1889-1933
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luca.ghedini@gmail.com - CC BY-SA 2.5
Elggren, Leif
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Neozoon - CC0 1.0
Montalivet, Jean-Pierre Bachasson, comte de, 1766-1823
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Public Domain
Abba, Marta.
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USNHC - Public Domain
Jeffers, William N. (William Nicholson), 1824-1883