Citation Styles

How often do I cite?

  • Remember: one citation at the end of a string of sentences or a paragraph cannot “cover” the entire section.
     
  • Cite a source the first time it is used in each paragraph.
     
  • Every sentence thereafter in the paragraph that uses information from this same source must contain either a signal phrase or a citation clearly indicating where the information came from.
     
    • Note: always use a citation (even if you also use a signal phrase) every time you quote material.

In-text Citation Placement

Where in the sentence does my in-text citation go?

  • If you name your source(s) in a given sentence, a parenthetical citation containing only the year always follows immediately after the name(s) of the author(s). Example: In contrast to earlier work by Abbott and Costello (1999), Laurel and Hardy (2008) propose an altogether different model for optimizing hat density …
     
  • If you do not explicitly name your source(s) in a given sentence, a single parenthetical citation goes at the end of the sentence or clause it covers, (Goffman, 1974), inside the punctuation, like this (Melville, 1851).
    • “If the sentence ends with a quotation, close the quote, then place the citation between the quotation marks and the punctuation, like this” (Woolf, 1931, p. 14).
       
  • Do not insert spaces between a parenthetical citation and the punctuation that follows it.

In the paragraph below, the  parenthetical in-text citations are highlighted in yellow, and the signal phrases are in blue. Note that the second sentence is common knowledge, whereas the final sentence is clearly the opinion of the author.

Red and yellow are the best colors with which to decorate your restaurant because they induce feelings of hunger (Smith & Jones, 2009). Consider popular fast-food chains, which often use red and yellow in their advertising and décor. According to Smith and Jones’ study (2009), restaurant customers felt more energized in red and yellow environments, which encouraged them to order more food. The same study indicated that patrons felt relaxed in blue and purple environments, which encouraged them to “spend more time considering the menu options and eat at a slower pace” (p. 29). Although blue décor can give your restaurant a more casual, laid-back feel (Kramer, 1999)Smith and Jones believe it encourages patrons to linger at their tables without ordering additional food or beverages. Accordingly, it is difficult to identify a popular chain restaurant that decorates with calmer hues.

For more information, see the TPO's Citing Responsibly in APA.

Difference between List of References and a Bibliography

A List of References includes all works cited in a text

A Bibliography lists all works cited and consulted


For papers, check with your professors for their preference. Thesis Processing prefers a List of References for the following: 

  • Thesis
  • Capstone project report
  • MBA report
  • Dissertation

Same Author, Multiple Works

When citing multiple sources by the same author from the same year, list them in alphabetical order by title in the List of References  (ignoring initial "a," "an," or "the") and append a lowercase letter to the year.

R: Hawthorne, M. (2006a). The cannibal’s dilemma: An unnatural history of four siblings. New York, NY: Penguin.

T: (Hawthorne, 2006a)

R: Hawthorne, M. (2006b). Having people for dinner: A guide for the home cook. New York, NY: Penguin.

T: (Hawthorne, 2006b)


When citing multiple sources by the same author with different years, list them in chronological order.

R: Hawthorne, M. (2006). The cannibal’s dilemma: An unnatural history of four siblings. New York, NY: Penguin.

R: Hawthorne, M. (2008). Regrets. New York, NY: Penguin.

 

Multiple Sources in One Citation

Source Generic Example with Rules Actual Example
Same author, same year, different sources
Source 1

R: Author, A. A. (Year published + a). Title of book in sentence case and italics. City, State: Publisher.

T: (Author, year + a)

R: Hawthorne, M. (2006a). The cannibal’s dilemma: An unnatural history of four siblings. New York, NY: Penguin.

T: (Hawthorne, 2006a)

Source 2

R: Author, A. A. (Year published +b). Title of book in sentence case and italics. City, State: Publisher.

T: (Author, year + b)

R: Hawthorne, M. (2006b). Having people for dinner: A guide for the home cook. New York, NY: Penguin.

T: (Hawthorne, 2006b)
Combined

T: (Author year + a, year + b)

T: (Hawthorne 2006a, 2006b)

Same author, different year, different sources
Source 1

R: Author, A. A. (Year published). Title of book in sentence case and italics. City, State: Publisher.

T: (Author, year)

R: Hawthorne, M. (2006). Having people for dinner: A guide for the home cook. New York, NY: Penguin.

T: (Hawthorne, 2006)

Source 2

R: Author, A. A. (Year published). Title of book in sentence case and italics. City, State: Publisher.

T: (Author, year)

R: Hawthorne, M. (2008). Regrets. New York, NY: Penguin.

T: (Hawthorne, 2008)
Combined

T: (Author, year 1, year 2)

T: (Hawthorne, 2006, 2008)

Different authors, different years within one citation
Combined

Separate two or more references with a semicolon, and place in alphabetical order; in the same order in which they appear in the reference list.

R: Ensure all authors appear in list of references

T: (Author 1, year; Author 2, year; etc.)

(Hawthorne, 2006b; Norton, 1998; Stulberg, 2014)

(Nekeip & Nywdlog, 2005; Qaga, 2007; Romato, Trange, & Bemon, 1995).

 

Title Case and Sentence Case Difference

Title Case: To Capitalize or Not: A Brief Tutorial

Sentence case: To capitalize or not: A brief tutorial

When Do I Need to Add Page Numbers?

For direct quotes, add page numbers to the in-text citation only.

Example: (Haynes, 2009, p. 70)


For book chapters, include page-number range in List of References/Bibliography.

Example: Cordesman, A. H., Mausner, A., & Kasten, D. (2009). Introduction. In J. Smith (Ed.), Winning in Afghanistan: Creating Effective Afghan Security Forces (pp. 1–12). Washington, DC: Center for Strategic and International Studies.

URLs

  • Include a retrieval date if the source material has no date.
     
  • Do not add a period at the end of the URL.
     
  • A URL does not belong in an in text-citation. Ever.

Author as Publisher

When the author and publisher are the same, use the word "Author" as the name of the publisher in the reference list citation.

Department of Defense. (2012, April 16). Identification (ID) cards required by the Geneva Convention (DOD Instruction 1000.01). Washington, DC: Author.

Author Names

Do not include honorifics (Dr., Col., Professor, etc.) when citing author names.

Et al. / Multiple Authors of a Single Work

For examples of how to properly incorporate the citation into your text and references, see row one.

# Authors of a single work First citation
in signal-phrase format
Subsequent citations First citation
in parenthetical format
Subsequent citation Reference List

One

Walker (2007) reported that ...

Walker (2007) reported that ...

Your citation goes at the end of the sentence (Walker, 2007).

Your citation goes at the end of the sentence (Walker, 2007).

Walker, V. (2007). [then the remaining reference information]
Two

Walker and Allen (2004)

Walker and Allen (2004)

(Walker & Allen, 2004)

(Walker & Allen, 2004)

Walker, V., & Allen, R. L. (2004).
Three, Four, or Five List all authors List just first author + "et al." List all authors List just first author + "et al." List all authors
Bradley, Ramirez, Soo, and Walsh (2006) Bradley et al. (2006) (Bradley, Ramirez, Soo, & Walsh, 2006) (Bradley et al., 2006) Bradley, K. S., Ramirez, H., Soo, T., & Walsh J. (2006).
Six or Seven Wasserstein et al. (2005) Wasserstein et al. (2005) (Wasserstein et al., 2005) (Wasserstein et al., 2005) List all authors. (2005).
Eight or More as above as above as above as above List first six authors, then insert (...) and finally add the last author's name. (2005).
Groups (readily identified through abbreviation) as authors National Institute of Mental Health (NIMH, 2003) NIMH (2003) (National Institute of Mental Health [NIMH], 2003) (NIMH, 2003) National Institute of Mental Health. (2003).
Groups (no abbreviation) as authors University of Pittsburgh (2005) University of Pittsburgh (2005) (University of Pittsburgh, 2005) (University of Pittsburgh, 2005) University of Pittsburgh. (2005).

 Adapted from American Psychological Association. (2010). Publication Manual of the American Psychological Association (6th ed.). Washington, DC: Author.

Secondary Sources

A secondary source is a source that cites some other work that you discuss in your text.

Whenever possible, consult primary sources and your sources’ sources yourself. Upon investigation of the primary source, you may find you disagree with the secondary source author’s analysis or methods. Only use secondary sources when the primary source is unavailable.


How to Incorporate Secondary Sources

The following passage incorporates a properly credited secondary source. The secondary source information is highlighted in yellow; the primary source information is highlighted in blue.

Walker (2008) describes data collected in 1999 by Miguel Roig that correlates students’ inadequate paraphrasing to poor reading comprehension. Citing Roig’s data, Walker explains that “students do in fact possess skills necessary for paraphrasing but … may be impeded from applying those skills when dealing with rigorous text” (p. 387).

Note: Include  only  the  secondary  source  (the  source  you  consulted)  in  your  reference  list.