What is a citation?
A citation provides enough information to enable a reader to find the same original source material. Typically, this will include author, title of text, date of publication, place of publication, and publisher. Try out Columbia University Library's Citation Finder.
When to cite sources
You must cite all sources that have directly or indirectly contributed to your analysis, synthesis, and/or argument in the work you submit.
You should quote your sources when it is important to convey the original author’s precise words.
- If you use the exact text – words, phrases, sentences – you must enclose them in quotation marks and cite.
- Short quotes – words and phrases – can be embedded into the text you write. Longer quotes – sentences and paragraphs – should be indented and separated from your words.
If you rewrite the original text in your own words, you must cite the source.
If you summarize the argument or data of another author, you must cite the source.
You must cite any text you read that helped you think about your paper even if you do not reference it directly in the text of your paper.
If a person assisted you in clarifying your thoughts – either in conversation or email correspondence – you must cite this source.
One way might be to acknowledge in a footnote connected to your paper’s title or opening sentence your indebtedness to a book or person (noting the date(s) of any relevant conversation or correspondence). Alternatively, for a more significant piece of work – such as an independent study or senior thesis – you can include a paragraph of acknowledgements, noting the range of assistance you received from many people.
Common knowledge is information that a reader can reasonably be expected to know. It does not need to be cited.
- For example, “Barack Obama, the former President of the United States, was a student of Columbia College” can be considered to be common knowledge and does not need to be referenced.
However, common knowledge does not include opinion.
- For example, you might agree with the statement “Columbia College is the best college” – but this is an opinion, not common knowledge and to make this case you would have to cite sources and data that support the supposition.
You should therefore be careful in the assumptions that you make in assessing what might be considered common knowledge.
Moreover, what might be common knowledge in one discipline might not be common knowledge in another discipline. It is important, then, to learn from your instructor the expectations for citing common knowledge in any given class.
If in any doubt, err on the side of caution and cite your source.
How to Cite Sources
Learning to cite correctly can be challenging. There are many different citation styles, which are often discipline- or division-specific. You should seek guidance from your instructor or Teaching Assistant to ensure that you understand the citation expectations for any given class.
An invaluable resource is Charles Lipson’s book “Doing Honest Work in College : How to Prepare Citations, Avoid Plagiarism, and Achieve Real Academic Success” Published in 2008 by University of Chicago Press, this book is available through Columbia University Libraries online catalog CLIO
In addition, Jeremiah Mercurio, Librarian in Butler Library, can help you create bibliographies and cite sources using a variety of citation styles and software, and can also help you understand ethical research practices with proper citations. Each semester at Butler Library there are a series of ongoing citation management workshops that teach students how to use Zotero.
The most common citation styles are:
Mathematics and Science
American Chemical Society (ACS) – Chemical Sciences
American Institute of Physics (AIP) - Astronomy, Astrophysics, and Physics
Council of Science Editors (CSE) – Biological Sciences
American Mathematical Society (AMS) - Mathematics
American Society of Mechanical Engineers (ASME) - Mechanical Engineering
Institute of Electrical and Electronics Engineers (IEEE) - Electrical Engineering
American Society of Civil Engineers (ASCE) - Civil Engineering
Association for Computing Machinery - Computer Science
American Anthropological Association (AAA) – Anthropology and Ethnography
Chicago Manual of Style – History, Economics, Business, & Fine Arts