Richardson, John Atkin
Prentice-Hall, 1977
Buku Teks
Sudjic, Deyan, author
Mitchell Beazley, 1986
Buku Referensi
edited by Martin Edwards
Foulsham, 1993
Buku Referensi
Scott, Bill, author
Ure Smith , 1976
Buku Teks
Board, Niir
Asia Pacific Business Press, [tt]
Buku Teks