1. National Academy of Sciences & National Research Council. Resources and man. W H Freeman Company, San Francisco (1969)
2. Meadows, H M et al.: The limits to growth. Pan Books (1972)
3. State or Oregon Legislation 1972:459.810-459.890 (Oregon Bottle Bill)
4. Boustead, I.: The milk bottle. Open University Press, Milton Keynes (1972)
5. Hannon, B M.: System energy and recycling: a study of the beverage container industry. ASME Paper No 72-WA/Ener3 (1972)