Bibliography

1. http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/asthma/asthma-symptoms-causes-risk-factors/symptoms.html

2. http://www.mayoclinic.org/diseases-conditions/asthma/in-depth/asthma-medications/art-20045557

3. http://www.aaaai.org/

4. http://www.nhlbi.nih.gov/

5. http://www.mayoclinic.org/

6. http://www.webmd.com/