edited by Priscilla Martin
Macmillan, 1983
Buku Teks
Overton, Bill
Macmillan Education, 1987
Buku Teks
Murry, John Middleton
Oxford University Press, 1949
Buku Teks
Lelyveld, Toby
Western Reserve University, (1960)
Buku Teks
Mahood, M. M.
Routledge , 1988
Buku Teks