Kalijarvi, Thorsten V., author
Thomas Y. Crowell, 1954
Buku Teks
Kegley, Charles William, Jr., author
St. Martin`s Press, 1997
Buku Teks
Routledge, 1995
Buku Teks
by Steven L. Spiegel [and others]
Thomson Wadsworth, 2005
Buku Teks
Lerner, Max, author
Simon and Schuster , 1962
Buku Teks