1. Burdon-Sanderson, J.S. (1893) Inaugural address. Nature, 48, 464–472
2. Tansley, A.G. (1904) The problems of ecology. New Phytologist, 3, 191–200
3. Elton, C. (1927) Animal Ecology. Sidgwick & Jackson, London
4. Ricklefs, R.E. (1973) Ecology. Nelson, London
5. Krebs, C.J. (1972) Ecology. Harper & Row, New York