Foster, Douglas
Longman, 1972
Buku Teks
Douglas, Colin
Heinemann, 1991
Buku Teks
Botting, Douglas
Harper & Row, 1973
Buku Teks
Douglas Jaga
Dewan Bahasa dan Pustaka , 1998
Buku Teks
Stewart, Douglas Alexander, 1913-, author
The Australian Broadcasting Commision, 1977
Buku Teks