Dobbs, Michael
Harper Collins, 2002
Buku Teks
Leeflang, Winston
In de Knipscheer, 1992
Buku Teks
Cowles, Virginia
Harper and Brothers, 1953
Buku Teks
edited by William Dodge Lewis, Henry Seidel Canby, Thomas Kite Brown
John C. Winston, 1942
Buku Referensi
Churchill, Winston, Sir, 1874-1965
Simon and Schuster, 1946
Buku Teks