1. Montreal Protocol to Reduce Substances That Deplete the Ozone Layer Report, Final Report, UN Environmental Program, New York, 1987.
2. Molina, M.J., and S.F. Rowland,Nature 249: 810–814 (1974).
3. Wijs, J.J.A.,Analyst 54:12–14 (1929).
4. Official Methods and Recommended Practices of the American Oil Chemists' Society, 4th edn., edited by D. Firestone, American Oil Chemists' Society, Champaign, 1989.
5. Ibid., Method Tg 3a-64.