Green, Michael, author
UNESCO, 1973
Buku Teks
Sharp, Mick
London Blandford 1997,
Buku Referensi
Walker, Gilbert
Heimann , 1957
Buku Teks
Churchill, Winston, Sir, 1874-1965, author
Dodd, Mead, 1956
Buku Teks
Jack, Ian
Secker & Warburg , 1987
Buku Teks