3ASTM D5504-01 Standard test method for determination of sulfur compounds in natural gas and gaseous fuels by gas chromatography and chemiluminescence[ S]. ASTM, 2006.
4ASTM.Standard Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chroma-tography and Chemiluminescence. ASTM D5504-01 . 2006