1. Wittenauer, R., Smith, L., & Aden, K. (2013). Background paper 6.12 osteoarthritis. Geneva: World Health Organization.
2. Brown, T. E. (2009). Arthritis & arthroplasty: The knee. Amsterdam: Elsevier Health Sciences. pp. 4–5.
3. Woolf, A. D., & Pfleger, B. (2003). Burden of major musculoskeletal conditions. Bulletin of the World Health Organization, 81(9), 646–656.
4. Neogi, T. (2013). The epidemiology and impact of pain in osteoarthritis. Osteoarthritis and Cartilage, 21(9), 1145–1153.
5. Heller, M. P. S. (2006). Is Asia prepared for an aging population? (No. 6–272). Washington, DC: International Monetary Fund.