%0 Journal Article %A F. F. Hafez %A Sheila M. Stewart %A M. Eileen Burnet %T Penicillin Levels in Sputum %D 1965 %R 10.1136/thx.20.3.219 %J Thorax %P 219-225 %V 20 %N 3 %U https://thorax.bmj.com/content/thoraxjnl/20/3/219.full.pdf