History Ireland
Tit-for-tat: the War of Independence in the northern counties
open_in_newarticle, 2012
National Archives UK
Irish Settlement: Proposals of the British government
open_in_newdocument, 20 July 1921

Bicycles, Barracks & Bandoliers
Memo regarding Catholic recruitment in the RUC and USC
memo, March 1922
Houses of Oireachtas
Correspondence between de Valera and Lloyd George
open_in_newdebate, 14 September 1921
Decade of Centenaries timeline
Ballytrain RIC barracks captured and sacked by the IRA.
photograph, 1920
UCD History Hub
Arthur Griffith, Sinn Fein and the IRB (The Irish Revolution Lecture 3)
podcast, 2014