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unknown - CC BY 2.5
Brian Leon - CC BY 2.0
PD-USGov - Public Domain
Harry Miller Lydenberg - Public Domain
Public Domain
author - Public Domain
National Science Foundation - Public Domain
Xavier Sébillot - Public Domain
unknown<br />Original uploader - Public Domain
Theodor John - Public Domain
Spencer Gore - Public Domain
Attilio Simonetti - Public Domain
James E. Purdy - Public Domain
Samuel Willard - Public Domain
Napoleon Sarony - Public Domain
germany - Public Domain
unknown - Public Domain
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unknown - CC BY 2.5
Moore, Harold E. (Harold Emery), 1917-1980
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Evans, Arthur, Sir, 1851-1941
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Dyer, Elisha, 1811-1890
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Brian Leon - CC BY 2.0
McCorkle, Jill, 1958-....
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PD-USGov - Public Domain
Withrow, Mary Ellen, 1930-
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Merrill, Paul W. (Paul Willard), 1887-1961
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Harry Miller Lydenberg - Public Domain
Moore, George Henry, 1823-1892
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Public Domain
Jesup, Morris K. (Morris Ketchum), 1830-1908
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Perlberg, William, 1899-1969
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Wilson, Joseph Lapsley, 1844-1928
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Rawlinson, Robert, 1810-1898
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Browne, Thomas M., 1829-1891
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author - Public Domain
Pearce, N. Bart (Nicholas Bart), 1828-1894
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National Science Foundation - Public Domain
Darnell, James E.
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Grigorescu, Nicolae, 1838-1907
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Xavier Sébillot - Public Domain
Rivière, Henri, 1864-1951
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Heer, Oswald, 1809-1883
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unknown<br />Original uploader - Public Domain
Bion, Wilfred R. (Wilfred Ruprecht), 1897-1979
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Theodor John - Public Domain
Bunge, Gustav von 1844-1920
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Public Domain
Sedgwick, John, 1813-1864
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Delessert, Benjamin, baron, 1773-1847
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Spencer Gore - Public Domain
Gore, Spencer Frederick, 1878-1914
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Davis, John E. (John Edward), 1913-1990
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Attilio Simonetti - Public Domain
Simonetti, Attilio, 1843-1925
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James E. Purdy - Public Domain
Straus, Isidor, 1845-1912
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Samuel Willard - Public Domain
Willard, Samuel, 1640-1707
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Napoleon Sarony - Public Domain
Wainwright, Marie, 1853-1923
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Green, John Richard, 1837-1883
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germany - Public Domain
Fritzsche, Hans, 1900-1953
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unknown - Public Domain
Pick, Ludwig, 1868-1944