When writing reports, essays or other assignments at the university, you need to support your arguments by referring to other published works. These works are your so-called sources. You will encounter a variety of possible sources, and it is important to learn how to identify, evaluate and choose between them.
There are a number of possible sources, ranging from academic works such as scientific articles and books, conference proceedings and research data, to official sources like government reports, patents, laws and regulations. Other common sources are illustrations in the form of photographs, figures, diagrams or maps. In some cases, less official sources like newspaper articles, interviews, webpages, blogs and twitter may also be accepted. You can read more about the different types and how to choose appropriate sources in the sections below.
A source can be either primary, providing first-hand evidence about something, or secondary, describing or discussing a primary sources. Since you are expected to have read and evaluated the works you cite, you should always identify and use the primary source. To cite a secondary source is generally to be avoided, unless the primary source is not available. You can learn more about primary and secondary sources in the section Primary vs secondary sources.
In Science, the main sources used are peer-reviewed scientific publications such as research articles published in academic journals or books in the form of research monographs. When writing assignments at university you will be expected to cite scientific material, and you therefore need to know how to identify these sources. You will find advice on how to determine whether a source is scientific in the section Scientific sources.
Sometimes, you will have to use sources that are not scientific, such as reports or webpages from public authorities, companies and organisations. Since these informal sources have not gone through peer-review, there is no previous quality control of the information. In this case, it is important that you review and evaluate the source yourself, before citing them in your work. You can learn more about to how to assess the credibility and usefulness a source in the section Evaluating informal sources.