Butler, David
Futura Publications, 1982
Buku Teks
Pirie, David B.
Routledge, 1985
Buku Teks
Barrat, David, author
Routledge, 1994
Buku Teks
Lee, Leonard
B.T. Batsford, 1995
Buku Teks
Butler, B. Robert
The Idaho State University Museum, 1968
Buku Teks