Duncan, Chester
Queenston House Publishing, 1975
Buku Teks
Duncan, Tom, author
John murray, 1985
Buku Teks
Duncan, MacGillivray
Blackie & Son, 1929
Buku Teks
Callow, Duncan
Chischester, 1995
Buku Teks
Duncan, Acheson J.
Richard D. Irwin , 1974
Buku Teks