Saowanee Woravutrangkul และ Suwannee Jarungjitaree. (2009) Effects of pursed lips breathing with forced expiration techniques and active cycle of breathing technique on airway clearance in chronic obstructive pulmonary disease patients. Mahidol University:ม.ป.ท.Saowanee Woravutrangkul และ Suwannee Jarungjitaree. 2009. Effects of pursed lips breathing with forced expiration techniques and active cycle of breathing technique on airway clearance in chronic obstructive pulmonary disease patients. ม.ป.ท.:Mahidol University;Saowanee Woravutrangkul และ Suwannee Jarungjitaree. Effects of pursed lips breathing with forced expiration techniques and active cycle of breathing technique on airway clearance in chronic obstructive pulmonary disease patients. ม.ป.ท.:Mahidol University, 2009. Print.