1. United States (2015) The national security strategy of the United States of America. [Washington]: President of the U.S. http://nssarchive.us/wp-content/uploads/2015/02/2015.pdf (Accessed April 30, 2018)
2. Humanitarian Assistance (2018) The organisation for economic co-operation and development (OECD) http://www.oecd.org/dac/stats/humanitarian-assistance.htm (Accessed April 2, 2018)
3. Glossary of Humanitarian Terms (2018) The World Health Organization http://www.who.int/hac/about/reliefweb-aug2008.pdf (Accessed April 2, 2018)
4. Bollyky TJ (2015) New, cheap, and improved
5. Whitesides GM (2012) The frugal way. The Economist-The World in 2011