1. Stroud, D. A., Reed, T. M., Pienkowski, M. W. & Lindsay, R. A. Birds, Bogs and Forestry (Nature Conservancy Council, Peterborough, 1987).
2. Bainbridge, I. P., Housden, S. D., Minns, D. & Lance, A. N. Forestry in the Flows of Caithness and Sutherland. Conservation Topic Paper No. 18 (Royal Society for the Protection of Birds, Sandy, UK, 1987).
3. Avery, M. I. J. appl. Ecol. 26, 957–966 (1989).
4. Mather, P. M. Computer Processing of Remotely Sensed Images (Wiley, London, 1988).