Chalfant, H. Paul
West Publishing Company, 1988
Buku Teks
Andersen, Margaret L., author
Thomson, Wadsworth, 2009
Buku Teks
Giddens, Anthony, author
W.W. Norton & Compan, 2005
Buku Teks
Hughes, Michael, author
McGraw-Hill, Higher Education, 2009
Buku Teks
Tischler, Henry L.
Wadsworth and Cengage Learning, 2014
Buku Teks