Keegan, William, author
Allen Lane, 1984
Buku Teks
Holmes, Martin
Westview Press, 1985
Buku Teks
Ben Jackson, Robert Saunders, editors
Cambridge University Press, 2012
Buku Teks
Blake, Robert, author
Fontana Press, 1990
Buku Teks
Blake, Robert, author
Fontana Press, 1985
Buku Teks