http://www.nhlbi.nih.gov/health/health-topics/topics/cf/causes.html
http://www.mayoclinic.com/health/cystic-fibrosis/DS00287/DSECTION=complications
http://www.cff.org/AboutCF/
http://www.mayoclinic.com/health/cystic-fibrosis/DS00287/DSECTION=complications
http://www.cff.org/AboutCF/