Keywords: McPherson Letter, 1813.jpg en Letter from Thomas Jefferson to Isaac McPherson 1813 discussing his views on intellectual property and the validity of Oliver Evans' patents 2014-04-10 11 30 04 http //memory loc gov/master/mss/mtj/mtj1/046/1000/1057 jpg Library of Congress Thomas Jefferson PD-old-100 Uploaded with UploadWizard Letters by Thomas Jefferson |