Marjorie Howes, John Kelly, editor
Cambridge University Press, 2008
Buku Teks
Fraser, G.S. (George Sutherland), 1915-
Published for the British Council and the National Book League by Longmans, 1965
Buku Teks
Shannon, William V.
Macmillan, 1963
Buku Teks
Shannon, Robert E.
John Wiley & Sons, 1980
Buku Teks
Shannon, David A.
Macmillan, 1995
Buku Teks