1. Chronic obstructive pulmonary disease: diagnostic considerations;Dewar;Am. Fam. Physician,2006
2. Chronic obstructive pulmonary disease: current burden and future projections;Lopez;Eur. Respir. J.,2006
3. World Health Organization Report. Burden of Chronic respiratory disease. (2011) available: http://www.who.int/respiratory/copd/burden/en/index.html (accessed 10.07.13).
4. Institute of Health Metrics and Evaluation. GBD Heat map. (2013). http://www.healthmetricsandevaluation.org/gbd/visualizations/gbd-heatmap (accessed 30.07.13.
5. American Thoracic Society (1995) Standards for the diagnosis and care of patients with chronic obstructive pulmonary disease. Am. J. Respir. Crit. Care. Med. 152(2): 77S-121.