Resources

http://www.tabletsmanual.com/wiki/read/pulmonary_emphysema_and_bronchitis

http://www.nhlbi.nih.gov/health/health-topics/topics/copd

http://www.menshealthcures.com/what-is-copd/

http://www.webmd.com/lung/copd/tc/chronic-obstructive-pulmonary-disease-copd-prevention