1. Archives
2. CVCE.eu, University of Luxembourg: Statement by the United Kingdom delegate (London, 28 March 1949). https://www.cvce.eu/en/collections/unit-content/-/unit/02bb76df-d066-4c08-a58a-d4686a3e68ff/304a94a5-251d-414a-93d0-f71c4a78118c/Resources#d663f3e7-4514-4970-9732-eab1ece68bb4_en&overlay
3. Towards the European Assembly and the Council of Europe. https://www.cvce.eu/en/recherche/unit-content/-/unit/04bfa990-86bc-402f-a633-11f39c9247c4/9c546388-b1f1-43d5-a961-e084af7d571d
4. Mackay papers, LSE archive, doc. 59: Minutes of the All-Party group meeting for European Unity, Wednesday, 21 April, 1948, House of Commons.
5. Beveridge, W. (1940/1998). Peace by federation? In J. Pinder (Ed.), Altiero Spinelli and the British federalists: Writings by Beveridge, Robbins and Spinelli, 1937–1943 (pp. 19–43). The Loathian Foundation Press.