APA refers to the writing style guidelines developed by the American Psychological Association and is used mostly by writers in the sciences (including the social sciences).

APA provide writers with a credible system for formatting their works and referencing any outside sources of information.

In APA style, when you use information or ideas from an outside source, either by paraphrasing or directly quoting them, you need to reference them in two ways:

  • In-text References: provide the name of the source (the author’s name or the title if no name is available) and the number of the page where the information is found in a parenthetical citation directly following the paraphrase or quote. Note: the name contained in the parenthetical citation will be the first item in the References page entry, giving the reader a direct path of reference.
  • References page: provide the full reference information for the source on your References page.

This way, the reader can follow the information in the parenthetical citation to the References page, which contains the full source information without disrupting the flow of your paper.

For the comprehensive APA guidelines, refer to The Publication Manual of the American Psychological Association or the official APA website. For more information on the APA handbooks, other official writing style manuals (like The Chicago Manual of Style), or other writing handbooks, visit our Writing Resources page.

Basic APA Formatting

  • Type or word-process your paper in a standard font and size (e.g., Times Roman, 12 pt.).
  • Left-align the text.
  • Double-space the text throughout the paper.
  • Set margins at one inch at the top, bottom and sides of the paper.
  • Create a page header (also known as the “running head”) at the top of every page. For a professional paper, include your paper title and the page number in the page header. For a student paper, include only the page number.
  • Create a title page with page number, a running head in the top left corner and the title, your name and institutional affiliation (or course number) centered above the middle of the page. Bold the title.
  • Indent the first line of each paragraph and all block quotations one-half inch from the left margin.
  • Italicize the titles of longer works (like a book) and put the titles of shorter works (like a poem) “in double quotation marks.”

In-Text References

APA calls for the author-date style of referencing, which requires the author’s name and the publication date of the source from which your quote or paraphrase is taken to be included in the text of your paper, along with the page number for a direct quote.

The full reference information for sources should be included on a separate References page. The in-text references can be done in three ways:

Both the author’s name and the publication date can immediately follow the quotation or paraphrase, in parentheses (separate the name and date with a comma):

One researcher has found that dreams can affect sleeping patterns (Johnson, 1991).

The author’s name can be mentioned in the text and only the publication date (and page number, if needed) included in the parentheses:

Freud states that “a dream is the fulfillment of a wish” (1998, p. 100).

Both the date and the authors name can be included in the text, making a parenthetical reference unnecessary (include a page number in parenthesis for a direct quote):

In 2003, Jones stated that student involvement was rising.

In some cases, you will need to format the reference a little differently. Here are some of the most common cases:

Two authors with the same last name and same publication date. When you have two or more sources by authors with the same last name, include the first initial of the author in the in-text citation.

While some doctors support this theory (J. Johnson, 2001), others do not (M. Johnson, 2001).

Two authors. If your source has two authors, include the last name of each (joined by the symbol “&”) in each in-text reference.

Psychologists hold that no two children are alike (Gesell & Ilg, 1996).

Three or more authors. If your source has three or more authors you only need to include the name of the first author, followed by the abbreviation et al.

Some theories rely on outdated clinical studies (Johnson et al., 1998).

No author (common with online sources). If you cannot find an author for the source, use the title in place of the author’s name.

Random testing for use of steroids by athletes is facing strong opposition by owners of several of these teams (“Steroids”, 2000 ).

No date. If there is not date for the source, use the abbreviation n.d. in its place. (If there is also no author, use the title as above and the abbreviation n.d.).

One study of students discovered that students succeeded with tutoring (Johnson, n.d.).

Personal communications, emails and broad ideas from works that you only refer to but do no paraphrase or quote from do NOT need to be included on the reference page, only cited in the text.

Note: An author can be a person or the name of an institution or corporation working collectively to author the piece.

Punctuating In-Text References

  • Any punctuation in your sentence must be placed outside of a direct quotation (after the quotation marks).
  • Any punctuation directly following a direct quotation (like a comma or a semi-colon) must be placed after the parenthetical reference.
  • If the parenthetical citation is at the end of a sentence, it must come before the period (or question/exclamation mark).
  • If a paraphrase or direct quotation in a sentence is followed by addition text (your own words), the parenthetical reference must directly follow the paraphrase or quote. (This avoids confusion about which words are from the source and which are your own.)
  • If you omit or add words to a direct quotation, indicate the omission by placing brackets around an ellipses in place of the omitted words ( [ . . .]) and indicate an addition by placing brackets around the added words ( add words [like this]).

Formatting Quotes

  • Place a direct quotation of forty words or less in double quotation marks within your text and follow it with a parenthetical reference that includes the specific page number in the source.
  • Place a direct quotation longer than forty words in free-standing block format without quotation marks (continue double-spacing). Indent each line five spaces and place the parenthetical reference at the end of the block quote, after the final punctuation mark. Do not to indent the following line of text unless you are starting a new paragraph.
  • When you quote something quoted in your source, set off the indirect quotation in single quotation marks within the larger direct quotation from your source.

References Page

The reference page appears at the end of your paper and should include all of and only the sources you cited within your text. By providing the full citation information for your sources in a reference page you enable readers to access your sources on their own. It very important to accurately reference your sources in scholarly and academic work, because doing so gives your work credibility and integrity.

Formatting the Reference Page

  • Title the page References. The word “References” should be centered at the top of the page in the same font and size as the rest of your paper, without underlining, italicizing, etc.
  • Alphabetize the list of works cited by the first item in each entry. The first item is usually the author’s last name (inverted to last name first in the entry), but if no author is available use the title of the work.
  • If you have two or more works by the same author, alphabetize the entries by the date of publication, starting with the earliest.
  • If an author appears as the sole author of one work and the first author in a group for another work, place the solely-authored work first.
  • If you have two or more works by different authors with the same last name, alphabetize the entries by the first initials of each author.
  • If you have two sources by the same author published in the same year, alphabetize the entries by the title and refer to them as (Author, Datea) and (Author, Dateb) in your in-text references.
  • If your source has twenty or fewer authors, list the last name and first/middle initials of all the authors.
  • If your source has more than 20 authors, list the last name and first/middle initials of the first 19 authors. Then, after the 19th author’s name, use an ellipsis in place of the remaining author names and end with the final author’s name.
  • The titles of works should be capitalized in the “sentence capitalization” form: only the first word and in some cases proper nouns, should be capitalized.
  • The first names of authors should be reduced to initials (unless you have to distinguish between two authors with the same last name and initials).
  • The first line of each entry should be flush with the left margin and the following lines should be indented five spaces.
  • Each entry should be double-spaced.
  • No additional spaces should be placed between entries.
  • The titles of smaller works (a chapter in a book, an article, a poem, a song, a short story, etc.) should be place in double quotation marks in the in-text references and left unformatted in the reference page entry.
  • The titles of larger works (an entire book, a film, a magazine, etc.) should be italicized.
  • Page numbers should be included in the full citation if the cited work was part of a larger body of work (like an article in a magazine).

Formatting References

The full reference of a work usually includes the author, the publication date, the title and publication information. Online source citations also include the date you accessed the work url (web address) at which your accessed it. Here are the formats of some common sources:

A Book with one Author

Bernstein, T. M. (1965). The careful writer: A modern guide to English usage . New York: Athenaeum.

A Book with two Authors

Strunk, W., Jr., & White, E. B. (1979). The elements of style (3rd ed.). New York: Macmillan.

A Source with a Corporate Author

U.S. Government Printing Office. (1973). Style manual (Rev. ed.). Washington, D.C.: Author

An Essay in an Edited Book or Collection

James, J. (1988). In S. Blake’s (Eds.), Reader for young adults. New York: Macmillan.

An Entry in an Encyclopedia

Bergmann, P. G. (1993). Relativity. In The new encyclopedia britannica (Vol. 26, pp. 501-508). Chicago: Encyclopedia Britannica.

A Magazine Article

Gardner, H. (1981, December). Do babies sing a universal song? Psychology Today , pp. 70-76.

A Journal Article

Harlow, H. F. (1983). Fundamentals for preparing psychology journal articles.Journal of Comparative and Physiological Psychology , 55, 893-896.

An Online Journal Article

Kenneth, I. A. (2000). A Buddhist response to the nature of human rights.Journal of Buddhist Ethics , 8(4).Retrieved February 20, 2001, from http://www.cac.psu.edu/jbe/twocont.html