Google Arts and CultureMemorandum from Arthur Griffith to de Valera on Ulster open_in_new document, 8 November 1921
UCD Digital LibraryGroup of IFS Army soldiers firing artillery on the Four Courts photograph, 28 June 1922
National Archives UK Cabinet Memorandum. Ireland – Capture of Four Courts. open_in_new document, 30 June 1922
Hathi Trust Digital LibraryThe struggle of the Irish people. Address to the Congress of the United States book, January 1921