1. J. Langan, P. Maroulis and R. Ridgeway, Solid State Technol., 39, 115 (1996).
2. K. Aitchison, A Partnership for PFC Emissions Reductions, Semicon Southwest (1998).
3. L. Mendicino, PFC Technical, Semicon West (1999).
4. L. Beu and P. T. Brown, Electrochem. Soc. Proc., 99-8, 1 (1999).
5. http://www.grida.no/publications/other/ipcc%5Ftar/?src=/climate/ipcc_tar/wg1/248.htm .