Selection of references used:
- 1: C.H.Frith, Cromwell, 1935, Mackays Limited Chatham (1935)
- 2: Malcomn Barber, The Two Cities, 1997, ISBN:0-415-06780-4, Routledge (1997)
- 3: Robert Fawtier (translation by Lionel Butler and R J Adam), The Capetian Kings of France, 1966, St. Martin's Press (1966), Oxfam bookshop