1. House of Commons Parliamentary Debates (HC Deb).
2. Heath, E. (1970). Speech to the Conservative Party Annual Conference. Blackpool, 1970.
3. Arthur, P. (1996). The Heath Government and Northern Ireland. In S. Ball & A. Seldon (Eds.), The Heath Government (pp. 1970–1974). Harlow: Pearson.
4. Ball, S. (1998). The Conservative Party since 1945. Manchester: Manchester University Press.
5. Bale, T. (2012). The Conservatives Since 1945: The Drivers of Party Change. Oxford: Oxford University Press.