edited by Beth A. Simmons and Richard H. Steinberg
Cambridge University Press, 2006
Buku Teks
Moon, Parker Thomas
Macmillan, 1926
Buku Referensi
Routledge, 1997
Buku Teks
Kolodziej, Edward A
Cambridge University Press, 2005
Buku Teks
Nicholson, Michael
Cambridge University Press, 1989
Buku Teks