Livingstone, David, 1813-1873. Letter to William C. Oswell, 4 April 1856. Images copyright National Library of Scotland. Creative Commons Share-alike 2.5 UK: Scotland (https://creativecommons.org/licenses/by-nc-sa/2.5/scotland/). As relevant, copyright Dr. Neil Imray Livingstone Wilson. Creative Commons Attribution-NonCommercial 3.0 Unported (https://creativecommons.org/licenses/by-nc/3.0/). 