University Newcastle
The University of Newcastle, 1973
Buku Referensi
Sawhill, John C.
Harper's Magazine, 1979
Buku Teks
Kynghee University Press, 1975
Buku Teks
Robertson, Ben, author
University of queensland press, 2010
Buku Referensi
Driver, Christopher
Hodder and Stoughton , 1971
Buku Teks