• Membrane systems for Nitrox
• uk.rec.scuba : Nitrox FAQ
• Nitrox Course - PDF version - another copy

• Trimix and heliox diving
• The narcosis of trimix and the calculation of END (and links)
• main masa.net page
• Rebreather, Oxygen, Nitrox, Trimix & Heliox FAQ

• Comex

• properties from webelements (on-line periodic table)
• production
• praxair

Air is a mixture of gases. It contains different percentages of nitrogen (78.084%), oxygen (20.946%), argon (.934%), carbon dioxide (.033%), and other gases (.003%).