1. American Lung Association Asthma & Children Fact Sheet http://www.lung.org/lung-disease/asthma/resources/facts-and-figures/asthma-children-fact-sheet.html
2. American Lung Association. Asthma in Adults Fact Sheet http://www.lung.org/lung-disease/asthma/resources/facts-and-figures/asthma-in-adults.html
3. Global surveillance, prevention and control of chronic respiratory diseases: a comprehensive approach 2007 http://whqlibdoc.who.int/publications/2007/9789241563468_eng.pdf
4. Centers for Disease Control and Prevention (CDC) CDC Vital Signs. Asthma in the US. Growing every year 2011 http://www.cdc.gov/VitalSigns/Asthma
5. American Lung Association. Lung Disease Data: 2008 http://www.lung.org/assets/documents/publications/lung-disease-data/LDD_2008.pdf