edited by P. McConvell and N. Evans
Oxford University Press, 1997
Buku Teks
Kelly, Robert L.,author
Wadsworth, 2010
Buku Teks
SPAFA, 1984
Buku Referensi
edited by Mari Pritchard Parker, Elvio Angeloni
McGraw-Hill, 2013
Buku Teks
Crawford, R.M.
Hutchinson's University Library, 1955
Buku Teks