Rogers, Katherine M
Harvester Wheatsheaf, 1990
Buku Teks
Matchinske, Megan, author
Cambridge University Press, 1998
eBooks
Scott, P. J. M.
New Jersy Vision and Barnes, 1984
Buku Teks
Adelstein, Michael E.
Twayne Publishers, 1968
Buku Teks
Cambridge University Press, 1998
eBooks