Google Arts and CultureMemorandum from Arthur Griffith to de Valera on Ulster open_in_new document, 8 November 1921
History Ireland Tit-for-tat: the War of Independence in the northern counties open_in_new article, 2012
Warwick Digital CollectionsImage of Sackville Street after Rebellion in Dublin, April, 1916 booklet, April 1916