Chilcote, Ronald H., author
Routledge, 2000
eBooks
Palmer, Monte, author
Thomson, 2006
Buku Teks
Curtis, Michael, author
Harper & Row, 1978
Buku Teks
Christian Soe
McGraw-Hill, 2004
Buku Teks
Barringron, Lowell, author
Wadsworth and Cengage Learning, 2013
Buku Teks