http://encyclopedia.airliquide.com/encyclopedia.asp?LanguageID=11&CountryID=19&Formula=&GasID=0&UNNumber=&EquivGasID=0&VolLiquideBox=&MasseLiquideBox=&VolGasBox=&MasseGasBox=&RD20=29&RD9=8&RD6=64&RD4=2&RD3=22&RD8=27&RD2=20&RD18=41&RD7=18&RD13=71&RD16=35&RD12=31&RD19=34&RD24=62&RD25=77&RD26=78&RD28=81&RD29=82