Citations have the same three elements regardless of source:
The page or paragraph number where you find information is required for all quotations but is optional for paraphrased information. Citations in your paper are necessary to provide credit to the proper sources; failure to cite properly could result in plagiarism.
Some good guidelines for citing your work are to cite anything that includes actual statistics or figures (i.e., "Fifty percent of the population believes..."). It is not necessary to cite common knowledge (i.e., you do not need to cite that the Earth is round). You will credit a source in each sentence that references material from a source. For examples of how often to cite a source in a paragraph, see our examples in the Citing Sources Properly section.
Here is an example of citations within a paragraph:
Researchers found many students are highly confused about citation (True & Noble, 2009). They also indicated some students receive erroneous information about citations or some professors are too lenient with them, causing even more confusion (True & Noble, 2009). In fact, Jones (2011) found 99 out of 100 students agreed citing work could seem like a "complex, maddening process" (p. 64).
In this example, note four main elements:
1. Sources are cited after each sentence in which they are used (rather than just at the beginning or end of a paragraph), even if each sentence uses the same source.
2. Parenthetical citations appear within the ending punctuation of a sentence.
3. Publication years appear after the authors for in-text citations (i.e., the in-text citation of True and Noble), while quotation page numbers appear after the quotation.
4. The full word and is used for in-text citations, while the ampersand symbol (&) is used for parenthetical citations.
Citation issues can appear when writers use too much information from a source, rather than including their own ideas and commentary on sources' information. Here are some factors to consider when citing sources:
1. Did I provide adequate commentary on the cited material?
Remember that the cited material should illustrate rather than substitute for your point. Make sure your paper is more than a collection of ideas from your sources; it should provide an original interpretation of that material. For help with creating this commentary while also avoiding personal opinion, see our Commentary vs. Opinion resource.
2. Did I begin and end my paragraphs in my own voice?
The opening sentence of each paragraph should be your topic sentence, and the final sentence in the paragraph should conclude your point and lead into the next. Without these aspects, you leave your reader without a sense of the paragraph's main purpose. Additionally, the reader may not understand your reasons for including that material.
3. Have I used the cited material to support my specific thesis?
All material that you cite should contribute to your main argument (also called a thesis or purpose statement). When reading the literature, keep that argument in mind, noting ideas or research that speaks specifically to the issues in your particular study. See our synthesis demonstration for help learning how to use the literature in this way.
4. Have I relied too heavily on one source?
Most research papers should include a variety of sources from the last 3-5 years. You may find one particularly useful study, but try to balance your references to that study with research from other authors. Otherwise, your paper becomes a book report on that one source and lacks richness of theoretical perspective.
5. Have I included too many direct quotations?
Direct quotations are best avoided whenever possible. While direct quotations can be useful for illustrating a rhetorical choice of your author, in most other cases paraphrasing the material is more appropriate. Using your own words by paraphrasing will better demonstrate your understanding and will allow you to emphasize the ways in which the ideas contribute to your paper's main argument.