UCD Digital LibraryGroup of IFS Army soldiers firing artillery on the Four Courts photograph, 28 June 1922
National Archives UK Letter from General Smuts to Eamon de Valera open_in_new letter, 4 August 1921
Hathi Trust Digital LibraryThe struggle of the Irish people. Address to the Congress of the United States book, January 1921
Decade of Centenaries timelineIreland’s Solemn League and Covenant: Anti-conscription protest form document, April 1918
RTE Century IrelandBetween armed rebellion and democratic revolution: the Irish Question in 1917 open_in_new article, 2017