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University Library


A library research guide for Biology.

Citation Basics

Why Cite?

You cite sources in your research projects for several reasons:

  • To show your readers you've done proper research by listing the sources you used to get your information;
  • To give credit to other researchers and acknowledging their ideas;
  • To avoid plagiarism by indicating which words and ideas you used are the work of other authors;
  • To allow our readers to locate the sources you used by providing in-text citations, footnotes, bibliographies or reference lists.


This brief video from Suffolk Community College explains what it means what citing is and how it works:


A "citation" is the way you tell your readers that certain material in your work came from another source. It also gives your readers the information necessary to find that source again, including:

  • the name of the author(s)
  • the title of the work
  • the name of the organization or publication that published the work
  • the date it was published
  • the volume, issue and/or page numbers of the work
  • whether the work is a print or electronic source
  • the name of the database where the source was found

Whenever you borrow words or ideas, you need to acknowledge the source. You need to cite:

  • whenever you use quotes
  • whenever you paraphrase 
  • whenever you use an idea that someone else has already expressed
  • whenever you refer to the work of another
  • whenever someone else's work has been critical in developing your own ideas
In other words ... if it did not come out of your own head, cite the source!

The image below shows all the kinds of information sources that can be cited ... basically, you can cite almost anything. In college research projects you will typically cite Journal and Magazine Articles, Books and e-Books, Webpages, News Articles, and Dissertations ... putting it metaphorically, that's the yoke of the egg. But there are all kinds of information sources you might use in your research, such as Tweets, Youtube Videos, Artwork, Interviews, Maps, TV Shows, Blog Posts, etc.. Just rememeber ... If you use it, you must cite it!

Image of egg with the names of information types that get cited: including Journal article, Book chapter, Newspaper story, e-book, Magazine article, Map, Interview, Tweet, etc.

You do not need to cite the source if the information is considered "common knowledge." 

What is Common Knowledge? Common knowledge is information that the average person would know or accept as reliable without having to look it up. This includes:

  • Information that most people know, such as that water freezes at 32 degrees Fahrenheit or that George Washington was the first US president.
  • Information shared by a cultural or national group, such as the names of famous heroes or events in the nation’s history that are remembered and celebrated.
  • Knowledge shared by members of a certain field, such as the fact that the necessary condition for diffraction of radiation of wavelength from a crystalline solid is given by Bragg’s law is "known" by physicists.

Keep in mind that what may be common knowledge in one culture, nation, academic discipline or peer group may not be common knowledge in another. So, when in doubt ... cite the source.

Image credit:


Academic disciplines have varying expectations for how to list citation information. But all the styles require the same basic information ... it is the order of that information that varies. In part, this is because different academic fields emphasize different elements of a source when referring to previous research.


When writing a research paper, the discipline determines the citation style you will use. You should also be sure to check with your instructor to find out which style your instructor prefers.

Here is a quick list of the core citation style guides are used in different disciplines:

  • AAA -- Anthropology
  • ACS -- Chemistry
  • AMA -- Medicine and Public Health
  • AP  -- Journalism
  • APA  -- Social Sciences
  • ASA -- Sociology
  • Bluebook -- Legal Documents
  • Chicago / Turabian  -- History, Art History  & some Social Sciences
  • CSE -- Sciences
  • IEEE -- Engineering
  • MLA -- English & some Humanities

The following guides provide in-depth information about the different citation styles:


To provide an overview of the difference between the three most commonly used citation styles, this chart from Purdue provides a side-by-side comparison of ALA 6th edition, MLA 7th edition, and the Chicago Manual of Style 16th edition.

  • to steal and pass off (the ideas or words of another) as one's own
  • to use (another's production) without crediting the source
  • to commit literary theft
  • to present as new and original an idea or product derived from an existing source

Plagiarism involves both stealing someone else's work and lying about it afterward … in other words, it is an act of fraud.


10 Types of Plagiarism


How to Avoid Plagiarism


Recommended Guides & Resources

Citation Tools

What is a citation tool?

A citation tool is a web-based or computer desktop application or resource that helps you organize, manage and format citations for your research.  There a two different kinds of citation tools: citation managers  and citation generators.

What is the difference?

Citation Manager: (also called a Reference Manager or Bibliographic Management Tool) Sometimes called "iTunes for your research," a citation manager is a comprehensive application that helps you store, organize, and sometimes search for citation sources, as well as format citations, bibliographies, in-text citations, footnotes, and research papers according to a chosen reference style. Citation managers can be web-based or computer desktop applications. Examples include EndNote, Mendeley, and Zotero.

​Citation Generator: (also called a Citation Machine or Citation Builder) A web-based resource that helps create formatted citations in a limited number of styles (MLA, APA, Chicago typically). Citation generators offer quick and easy steps to creating single citations that you can copy and paste into your research papers. Take a look at our list of citation generators for a comparison of features and links.


Image of Mendeley icon

Mendeley is a FREE reference manager that will automatically generate bibliographies; import and annotate PDFs; provide collaboration tools, and find relevant papers based on what you’re reading. It provides desktop software for Mac, Windows, Linux, and Android. Plus there is a website where you can access your library and papers from anywhere online and easily collaborate. You also have access to their handy mobile apps for iPad, iPhone, and Android.

Links and Resources

image of zotero icon

Zotero is a a FREE reference manager that works within your Firefox web browser. It is also available in a standalone version that allows you to use Zotero with other browsers (Chrome and Safari). Zotero allows you to store and organize citations as you find them. It also allows you to "drag and drop" citations to create your bibliography, create groups, add a wide variety of inforamtion items, store a snapshot of a website. And you can automatically format bibliographies and citations in MLA, APA, Chicago Manual of Style, and many other styles using Microsoft Word and LibreOffice plugins.

Links & Resources

Other Citation Managers

There is an array of citations managers out there to help you locate, manage, cite and format citations and information sources.  Below is a sampling of resources that are available. Some are free and others will charge a fee (but often at a discount for educational use and provide free trial periods).

Resources and Links:

Citation Generators

Do you need your citation formatted ... and you need it right now? Then a citation generator may be your answer. Citation generators will either auto-fill citation forms using information provided from website lookups OR provide a form for manual entry -- and then provide you with a formatted citation in a limited number of styles (typically MLA, APA or Chicago). Below is a list of some of the most popular FREE citation generators.

Take Note: Citation generators are very convenient but some can be prone to formatting errors. Double-checking citations with a style guide is highly recommended.

Resources and Links:

Citation Generators within SSU Article Databases

Some database vendors offer built in citation generators, e.g., EBSCOhost, OVID, Proquest, JSTOR, etc.. When searching in a database, look for words like “Cite Now” or “Cite This” or “Citation Format” because these are links to citation generators. You can find these in databases such as Academic Search Complete, PsycInfo, ABI/Inform, etc.