1. Mayo Clinic.Mayo Clinic ‐ diseases and conditions. diseases and conditions asthma.1988–2017. Available at:http://www.mayoclinic.org/diseases-conditions/asthma/basics/definition/con-20026992. Accessed May 14 2017.
2. World Health Organisation.Chronic respiratory diseases.2017. Available at:http://www.who.int/respiratory/asthma/definition/en/. Accessed May 14 2017.
3. Global Initiative for Asthma. .Global strategy for asthma management and prevention. Global strategy for asthma management and prevention.2016. ;www.ginasthma.orghttp://ginasthma.org/wp-content/uploads/2016/04/GINA-2016-main-report_tracked.pdf. Accessed May 11 2017.
4. National surveillance for asthma—United States, 1980–2004;Moorman JE;MMWR Surveill Summ,2007
5. Global strategy for asthma management and prevention: GINA executive summary