Fulbrook, Julian
Mansel, 1978
Buku Teks
editors, George S. Bridgges, Joseph G. Weis, Robert D. Crutchfield
Pine Force Press, 1996
Buku Teks
Rawlings, Philip, author
Longman, 1999
Buku Teks
Powell, Edward, author
Oxford University Press, 1989
Buku Teks
Rawlings, Philip, author
Longman, 1999
Buku Teks