RT Journal Article SR Electronic T1 High frequency oscillation and tracheobronchial clearance JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 842 OP 842 DO 10.1183/09031936.93.03070842a VO 3 IS 7 A1 CD Laros A1 CJ Westermann A1 VA Duurkens A1 DM Dolk YR 1990 UL http://erj.ersjournals.com/content/3/7/842.2.abstract