Elements of Reference List Entries

Reference list entries include the four elements of the author, date, title, and source.

This page describes each element in detail:

• the author element, including the format of individual author names and of group author names
• the date element, including the format of the date and how to include retrieval dates
• the title element, including the format of the title and how to include bracketed descriptions
• the source element, including the format of the source and how to include database information

View the reference examples to see the elements of reference list entries in action.

A summary of this guidance is presented on the page about the basic principles of reference list entries. Additional information and examples are available in Chapters 9 and 10 of the Publication Manual.

If a work does not have an author, date, title, or source, visit the page on how to adjust reference list entries when reference information is missing.

The author refers broadly to the person(s) or group(s) responsible for a work. An author may be

• an individual,
• multiple people,
• a group (institution, government agency, organization, etc.), or
• a combination of people and groups.

This element includes not only authors of articles, books, reports, and other works but also others who played primary roles in the creation of a work, such as editors of books, directors of films, principal investigators of grants, podcast hosts, and so on.

When you cannot determine who the author is, treat the work as having no author.

Follow these guidelines to format the author element. Additional guidelines for less common cases are provided in the Publication Manual.

• Invert all individual authors’ names, providing the surname first, followed by a comma and the author’s initials.

• Use a comma to separate an author’s initials from additional author names, even when there are only two authors. Use an ampersand (&) before the final author’s name.

• Provide surnames and initials for up to and including 20 authors. When there are two to 20 authors, use an ampersand before the final author’s name.

• When there are 21 or more authors, include the first 19 authors’ names, insert an ellipsis (but no ampersand), and then add the final author’s name.

• Use one space between initials.

• Write the author’s name exactly as it appears on the published work, including hyphenated surnames and two-part surnames.

• Retain the author’s preferred capitalization.

Group authors are often government agencies, nonprofit organizations, and task forces. Follow these guidelines to format the names of group authors in the reference list.

• Look at the title page or cover of the work to determine whether it has a group author or individual authors.
  • If the names of individuals are presented on the title page or cover, treat the work as having individual authors.
  • If only the name of the group is presented on the title page or cover, treat the work as having a group author, even if individuals are credited elsewhere in the work (e.g., in an acknowledgments section).

• Spell out the full name of a group author in the reference list entry, followed by a period.

• On a page from an organizational or government agency website, the organization or government agency itself is considered the author, unless otherwise specified. The author of a webpage or website may also be located on an “about us” or acknowledgments page.
• An abbreviation for the group author can be used in the text (e.g., NIMH for National Institute of Mental Health); however, do not include an abbreviation for a group author in a reference list entry.

• When numerous layers of government agencies are listed as the author of a work, use the most specific agency as the author in the reference (e.g., use “National Institute of Nursing Research” rather than “U.S. Department of Health and Human Services, National Institutes of Health, National Institute of Nursing Research”). The names of parent agencies not present in the group author name appear in the source element as the publisher.

The date refers to the date of publication of the work. The date will take one of the following forms:

• year only;
• year, month, and day (i.e., an exact date);
• year and month;
• year and season; or
• range of dates (e.g., range of years, range of exact dates).

When you cannot determine the date of publication, treat the work as having no date.

Follow the date format for the reference type as shown in the Publication Manual. Most references use only the year. Additional guidelines for less common cases are provided in the Publication Manual.

• Enclose the date of publication in parentheses, followed by a period

• For works from a reference category that includes the month, day, and/or season along with the year, put the year first, followed by a comma, and then the month and date or season.

• For unpublished, informally published, or in-progress works, provide the year the work was produced. Do not use “in progress” or “submitted for publication” in the date element of a reference.
• If a work has been accepted for publication but is not yet published, use the term “in press” instead of a year.

• If a work is an advance online publication, use the year of the advance online publication in the reference.
• When the date of original publication is approximate, use the abbreviation “ca.” (which stands for “circa”).

If a date of last update is available (such as for a webpage), use it in the reference. Do not include a date of last review in a reference because content that has been reviewed has not necessarily been changed.

Include a retrieval date only if the work is unarchived and designed to change over time. Most references do not include retrieval dates. Examples of some that do are in Chapter 10 of the Publication Manual and on the reference examples page.

When a retrieval date is needed, use the following format for it.

The title refers to the title of the work being cited. Titles fall into two broad categories:

• works that stand alone (e.g., whole books, reports, gray literature, dissertations and theses, informally published works, data sets, videos, films, TV series, albums, podcasts, social media, and works on websites) and
• works that are part of a greater whole (e.g., periodical articles, edited book chapters, TV and podcast episodes, and songs).

When a work stands alone (e.g., a report), the title of that work appears in the title element of the reference. When a work is part of a greater whole (e.g., a journal article or edited book chapter), the title of the article or chapter appears in the title element of the reference and the title of the greater whole (the journal or edited book) appears in the source element.

When the title of the work cannot be determined, treat the work as having no title.

Follow these guidelines to format the title element. Additional guidelines for less common cases are provided in the Publication Manual.

• For works that are part of a greater whole (e.g., journal articles, edited book chapters), capitalize the title using sentence case. Do not italicize the title or use quotation marks around it.

• For works that stand alone (e.g., books, reports, webpages), italicize the title, and capitalize it using sentence case.

• For book and report references, enclose edition information, report numbers, and volume numbers in parentheses after the title. Do not add a period between the title and the parenthetical information. Do not italicize the parenthetical information. If both edition and volume information are included, separate these elements with a comma, placing the edition number first.

• If a numbered volume has its own title, the volume number and title are included as part of the main title, rather than in parentheses.

• Finish the title element with a period. However, if the title ends with a question mark or exclamation point, that punctuation mark replaces the period.

To help identify works outside the peer-reviewed academic literature (i.e., works other than articles, books, reports, etc.), provide a description of the work in square brackets after the title and before the period. Capitalize the first letter of the description, but do not italicize the description.

Examples of works that include bracketed descriptions are some audiobooks, gray literature (e.g., press releases), audiovisual works (e.g., films, YouTube videos, photographs), software and mobile apps, data sets, manuscripts in preparation, and dissertations and theses. Bracketed descriptions are also used in social media references to indicate attached links or images.

The examples in the Publication Manual and on the reference examples page include bracketed descriptions where they are needed. When in doubt, include a description. Consistency of wording is helpful, but you may alter the wording shown in the examples to best convey the information readers need to understand the nature of the work.

The source indicates where readers can retrieve the cited work. As with titles, sources fall into two broad categories: works that are part of a greater whole and works that stand alone.

• The source for a work that is part of a greater whole (e.g., journal article, edited book chapter) is that greater whole (i.e., the journal or edited book), plus any applicable DOI or URL.
• The source for a work that stands alone (e.g., whole book, report, dissertation, thesis, film, TV series, podcast, data set, informally published work, social media, webpage) is the publisher of the work, database or archive, social media site, or website, plus any applicable DOI or URL.
• A location is not required in the source element for most works (e.g., do not include the publisher location for book references).
• Works associated with a specific location (e.g., artwork in a museum, conference presentations) include location information in the source and, depending on the work, may also include a DOI or URL.

If a work is not recoverable, treat it as having no source.

The format of the source varies depending on the reference type. The most common cases are presented next. Additional guidelines for less common cases are provided in the Publication Manual.

Database and archive information is seldom needed in reference list entries. For example, if you retrieved a work from an academic research database, the reference very rarely includes the name of the database or the URL of the work on the database.

Visit the page on database information in references to learn when and how to include database information in references.

Visit the page on DOIs or URLs to learn how to include DOIs and URLs in references.