The National Aeronautic and Atmospheric Administration'sGlenn Research Center. Gas Density Glenn research Center. grc.nasa.gov. [2015-08-29]. (原始内容存档于2013-04-14).
The National Aeronautic and Atmospheric Administration'sGlenn Research Center. Gas Density Glenn research Center. grc.nasa.gov. [2015-08-29]. (原始内容存档于2013-04-14).