Stroud, Angus
Routledge, 1999
Buku Teks SO
Trevelyan, George Macaulay, 1876-1962
Longmans, Green, 1948
Buku Teks SO
Stuart, Dorothy Margaret.
Macmillan, 1952
Buku Teks SO
Cash, Allen J.
The Automobile Association, 1987
Buku Referensi
Gooch, R.K. (Robert Kent), 1893-1982
D. Van Nostrad, 1937
Buku Teks