The following is a key to the sources mentioned in the comments column. It should not be taken as an exhaustive bibliography of the British Battalion in Spain, nor the International Brigades themselves.

Abbreviation	Source Details
BA	Bill Alexander, British Volunteers for Liberty. London: Lawrence and Wishart, 1982.
BC	Bob Clark, No Boots to my Feet: Experiences of a Britisher in Spain 1937-38. Student Bookshops, 1984.
C&P	Mike Cooper & Ray Parkes, We Cannot Park on Both Sides: Reading volunteers in the Spanish Civil War 1936-39. Reading: 2000.
C&R	D. Corkhill & S. Rawnsley (eds.), The Road to Spain: Anti Fascists at War 1936-1939. Fife: Borderline, 1981.
CH	Chris Hall, Not Just Orwell. Warren & Pell, 2009.
DH	David Hooper, No Pasarán! A Memoir of the Spanish Civil War. London: Avon, 1997.
ER	Esmond Romilly, Boadilla. London: Hamish Hamilton, 1937.
FR	Frank Ryan, ed., The Book of the XVth Brigade: Records of British, American, Canadian and Irish Volunteers in the XV International Brigade in Spain 1936-1938. Madrid: War Commissariat, 1938.
FT	Fred Thomas, To Tilt at Windmills: A Memoir of the Spanish Civil War. East Lansing: State University of Michigan Press, 1996.
GC	Geoffrey Cox, The Defence of Madrid. London: Victor Gollancz, 1937.
GO	George Orwell, Homage to Catalonia. London: Secker & Warburg, 1937.
HF	Hywell Francis, Miners Against Fascism: Wales and the Spanish Civil War. London: Lawrence and Wishart, 1984.
HS	H. Stratton, To Anti-Fascism by Taxi. West Glamorgan: Alun Books, 1984.
HS	Hugh Sloan, ‘Why I Volunteered’, Scottish Trade Union Review, 51, July-Sept 1991, pp. 30-31
HT	Hugh Thomas, The Spanish Civil War, 3rd edition. London: Penguin, 1990.
IBA	International Brigade Archive, Marx Memorial Library, Clerkenwell Green, London EC1
IM	Ian MacDougall (ed.), Voices from the Spanish Civil War: Personal Recollections of Scottish Volunteers in Republican Spain, 1936-1939. Edinburgh: Polygon, 1986.
IMD	Ian MacDougall, ‘Tom Murray: Veteran of Spain’ Cencrastus, 18, Autumn 1984, pp. 16-19.
IWMSA	Imperial War Museum Sound Archive, London.
JA	John Angus, With The International Brigade in Spain. Loughborough: 1983.
JC	Judith Cook, Apprentices of Freedom. London: Quartet Press, 1979.
JG	Jason Gurney, Crusade in Spain. London: Faber and Faber, 1974.
JH	James K. Hopkins, Into the Heart of the Fire: The British in the Spanish Civil War. California: Stanford, 1998.
JM	Joe Monks, With the Reds in Andalusia. Privately published, 1985.
JS	John Sommerfield, Volunteer in Spain. London: Lawrence and Wishart, 1937.
KW	Keith Scott Watson, Single to Spain. London: Arthur Baker, 1937.
LE	Lloyd Edmonds, Letters from Spain. Sydney: George Allen & Unwin, 1985.
LL	Laurie Lee, A Moment of War. London: Viking, 1991.
Manchester	Manchester Studies Collection, Tameside Local Studies Centre, Ashton-under-Lyne
MJ	Michael Jackson, Fallen Sparrows: The International Brigades in the Spanish Civil War. Philadelphia: American Philosophical Society, 1994.
MJH	M.J. Hynes, ‘The British Battalion of the XVth International Brigade’, Unpublished B.A. Dissertation, University of Manchester, 1985.
ML	Maurice Levine, Cheetham to Cordova. Manchester: Privately Published, 1984.
MOR	Michael O’Riordan, Connolly Column. Dublin: New Books, 1979.
NA	National Archives (formerly the Public Record Office), Kew
PHM	Peoples’ History Museum (formerly the National Museum of Labour History)
PT	Peter Thwaites, ‘The ILP Contingent in the Spanish Civil War’, Imperial War Museum Review, 1987, pp. 50-61.
RGASPI	International Brigade Collection, Russian Centre for the Preservation and Study of Recent Historical Documents, Moscow.
RS	Robert Stradling, Ireland and the Spanish Civil War. Manchester: Manchester University Press, 1999.
SH	Good to be Alive: The Story of Jack Brent. London: Lawrence & Wishart, 1954.
SW	Stanley Weintraub, The Last Great Cause: The Intellectuals and the Spanish Civil War. London: W.H. Allen, 1968.
TW	Tom Wintringham, English Captain. London: Faber & Faber, 1939.
VB	Vincent Brome, The International Brigades. London: Heinmann, 1965.
W&C	Don Watson & John Corcoran, An Inspiring Example: The North East of England and the Spanish Civil War 1936-1939. Newcastle: McGuffin, 1996.
WG	Walter Gregory, The Shallow Grave: A Memoir of the Spanish Civil War. London: Victor Gollancz, 1986.
WR	William Rust, Britons in Spain. London: Lawrence and Wishart, 1939.