edited David Marsh and Gerry Stoker
Macmillan, 1995
Buku Teks
Evera, Stephen van, author
Cornell University Press, 1997
Buku Teks
Johnson, Janet Buttolph, 1950-, author
CQ Press, 2012
Buku Teks
Garson, G. David., author
Holbrook Press, 1971
Buku Referensi
Le Roy, Michael K., author
Wadsworth, 2009
Buku Teks