References
- Holmes , A . 1965 . Principles of Physical Geology , 972 London : Nelson .
- Carson , R . 1963 . Silent Spring , London : Hamish Hamilton .
- Pretty , J . 2002 . The magic bean . Resurgence , Jan./Feb. : 20 – 21 .
- Centre for Environment and Society, University of Essex. At: http://www2.essex.ac.uk/ces (click on ‘research programmes’, then ‘sustainable agriculture')