Rothstein, Andrew, author
Penguin Books , 1950
Buku Teks
Fry, Peter Somerset, author
Routledge , 2001
Buku Teks
Marwick, Arthur
London MacMillan 1992
Buku Teks
Nevins, Allan, 1890-1971, author
Anchor Books, 1962
Buku Teks
Toynbee, Arnold J., author
Oxford University Press, 1954
Buku Teks