1. World Health Organisation. WHO disability assessment schedule 2.0 (WHODAS 2.0). Geneva: World Health Organisation; 2014.
2. Ray R. The Extent, Pattern and Trends of Drug Abuse in India-National Survey. Regional Office for South Asia: Ministry of Social Justice and Empowerment, Government of India and United Nations Office on Drugs and Crime; 2004.
3. Anand K. Assessment of burden and surveillance of major non-communicable diseases in India. New Delhi: World Health Organization, Regional Office for South-East Asia; 2000.