1. A review of conventional and emerging process technologies for the recovery of helium from natural gas;Rufford;Adsorpt. Sci. Technol.,2014
2. P. Haussinger, R. Glathaar, W. Rhode, H. Kick, C. Benkmann, J. Weber, et al., Noble gases, in: Ullmann’s Encyclopedia of Industrial Chemistry. John Wiley and Sons, Hoboken, NJ, USA, 2011, pp. 392–448.
3. R. Clarke, W. Nuttall, B. Glowacki, Endangered Helium: Bursting the Myth, The Chemical Engineer, Institution of Chemical Engineers, Rugby, UK, 2013, pp. 32–36.
4. Atmospheric composition and vertical structure;Schlatter,2009
5. Review of membranes for helium separation and purification;Scholes;Membranes,2017