Primary sources - scholarly articles, scholarly books, doctoral theses etc. where new research are published for the the first time are seen as primary sources. Primary sources consist of first-hand information or original data.
Secondary sources point toward one or more primary sources. Secondary sources are based on primary sources, for example by analysing, summarising and evaluating primary sources. Review articles, systematic reviews or meta-analyses are examples of secondary sources.
Primary Source - Example
An article about fall injuries among older Australians in community dwelling is published in the scholarly journal Gerontology 2005.
Secondary Source - Example 1
A review article published 2013 in the scholarly journal International Journal of Sociology and Social Policy , which discusses research about ageing in West Africa, cites the article in Gerontology from 2005.
Secondary Source - Example 2
An article about the relationship between leisure-time physical activity and fall injuries among middle-aged adults published 2015 in the scholarly journal American Journal of Preventive Medicine cites the article in Gerontology from 2005.
Secondary Source - Example 3
The book "Foot problems in older people" published in 2008 and targeted towards health care professionals cites the article in Gerontology from 2005.