Atomox has compiled various reference material regarding real gas blending and mixing for your personal use. The following links will redirect you to the page of interest:

• Measuring Helium - The principal of measurement used by the Atomox helium analyzers.
• Real Gas Mixing - A paper on "Calculation of Partial Pressures for High Pressure Gas Mixtures".
• Real Gas Volume - A table showing the "Volumetric Compressibility of Real Gases".
• Z Factor - A table of compressibility factors for 20 degC.
• Z Graphs - Graphs of compressibility factors for Air, Oxygen and Helium.