Measurement of the damping constant (the a-parameter) of several elements in several hydrogen and acetylene-oxygen flames using an absorption method W. W. McGee and J. D. Winefordner Journal of Quantitative Spectroscopy and Radiative Transfer Volume 7, Issue 1, January-February 1967, Pages 261-272 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVR-46J040F-1W&_user=1915929&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000055340&_version=1&_urlVersion=0&_userid=1915929&md5=67a51518be65b5bd84f31640fe4ff1e9