1. IPCC Fourth Assessment Report (AR4) by Working Group 1 (WG1) 2007, Changes in Atmospheric Constituents and in Radiative Forcing (Chapter 2).
2. US Environmental Protection Agency, 2006 (Retrieved 2012-10-05). .
3. PCC TAR WG1, 2001 (Retrieved 2012-10-05). .
4. Handbook of Chemistry and Physics;Lide,2004