Roysl Ministry Affairs, 1959
Buku Teks
McCormick, James M., author
Thomson, 2005
Buku Teks
Herrick, Christopher, author
Longman, 2003
Buku Teks
Brown, William Adams, author
Brookongs Institutons, 1954
Buku Teks
McCamy, James L., author
Alfred A. Knopf, 1952
Buku Teks