Longman, 1999
Buku Teks
Duesenberry, James S. (James Stemble), 1918-2009, author
Prentice-Hall, 1964
Buku Teks
Aschheim, Joseph, author
Johns Hopkins Press, 1961
Buku Teks
U.S. Govt. Print, 1968
Buku Teks
Polsby, Nelson W., author
Charles Scribner`s Sons, 1964
Buku Teks