Wrenn, Chase B., 1974-, author
Polity, 2015
Buku Teks
McCullagh, C. Behan, author
Routledge, 1998
Buku Teks
Marmysz, John, 1964-, author
Wadsworth and Cengage Learning, 2012
Buku Teks
Blundell, Nigel, author
Octopus Books Limited, 1980
Buku Teks
Dunham, Barrows, author
Little, Brown and Company, 1947
Buku Teks