We publish because we want to share our knowledge and, often, because we want recognition for our work. We acknowledge people’s ideas and findings by providing citations. Unfortunately, however, the rules regarding this common practice are hard to decipher, even for the best of us! We have created a series of articles to help you navigate various citation requirements. This article focuses on how to name the authors of cited works, including when to use the abbreviated Latin term “et al.” As with all advice, please make sure to follow the relevant journal guidelines concerning punctuation, citation style, etc. Sadly, publishers agree on few rules! Let’s start with some definitions.
What are the main types of citations?
When referring to published literature, provide details so that others can find and review the original material. In your research paper, you can make references to source materials using either endnotes and footnotes or in-text citations. Both styles require a reference list at the end of the document.
- In-text (or parenthetical) citations: When referencing other literature by author or title in the body paragraphs of your paper, you are using in-text citations. This method is also commonly known as “parenthetical citations” as the referencing information is often placed within parentheses.
- Endnotes and footnotes: Endnotes and footnotes are a convenient way to declutter your writing. They are simple notation systems that allow you to use numbers in the body of a text to reference a cited work. The number corresponds to further information or a citation entry found at the end of a manuscript (for endnotes) or at the bottom of the page where the cited reference is mentioned (for footnotes). These notations are rarely found in scientific writing; however, they are frequently used in the humanities and social sciences. Also, endnotes and footnotes replace parenthetical information that could include bibliographic data. Accordingly, if you use endnotes and footnotes, you should avoid parenthetical citations.
- Reference lists: A reference list compiles all the works cited within a document for ease of reference and is included at the end of a manuscript. It must be included regardless of how source material is acknowledged within the main body of your article.
What is “et al.”?
Latin terms regularly appear in academic writing. “Et al.” is one of the phrases you should know. It is an abbreviation of “et alii”, meaning “and others”, and it is used to denote a list of people. Its function is similar to that of “et cetera”, another common Latin phrase that is usually abbreviated as “etc.” and means “and the rest”.
What’s the difference between “et al.” and “etc.”?
As stated above, “et al.” is used strictly when talking about people, while “etc.” is only used for things. Apart from this key difference, they have the same function: replacing a list.
When do you use “et al.”?
We cannot stress this enough, but always double-check your journal or relevant style guide regarding Latin terms and citations. There is no uniform rule for “et al.”, but at least the phrase’s spelling is consistent. Always write “et al.” in lowercase (unless it begins a sentence) and include a period after “al.”, even when it appears in the middle of a sentence. The term “al.” is an abbreviation of “alii” and, the entire phrase “et al.” always follows at least one person’s name, job position, or title. With that said, “et al.” replaces author names in endnotes, footnotes, and in-text citations; however, it is NOT used in reference lists! The following section provides further information and examples.
How to cite references: dealing with author names
This section explains how to list authors in citations. The information is organized by the number of authors and citation type, and covers the most common style guides:
- American Psychological Association (APA) style;
- Chicago Manual of Style (Chicago style); and
- Modern Language Association (MLA) style.
*Some journals, like those in the Nature publication family, have their own referencing guidelines. When in doubt, double-check your journal’s requirements.
APA style: listing author information
The APA style is frequently used by social science professionals. Examples of book and journal citations are provided below. For information about other sources and special cases, click here; see also Publication Manual of the American Psychological Association, (6th ed., 2nd printing).
Note: APA uses the ampersand (&) to list authors.
Reference lists
The same author rules apply to all source media including books, print periodicals, electronic journals, etc. Also, since reading electronic journals has become the norm for academics, the APA recommends including a DOI number for each journal article referenced, even if you accessed the document in print. Do not include a period (.) after the DOI information.
| Number of authors | Notation |
| One | Books: [Last name], [First initial]. [Middle initial]. ([Year]). [Title of book: Capitalize first word of subtitle]. [City, State abbreviation/Country for non-US publications]: [Publisher]. Smith, M. T. (2017). Epigenetic mechanisms: An overview. Lima, Peru: PublishCo. Journals: [Last name], [First initial]. [Middle initial]. ([Year]). [Article title]. [Journal Title], [Volume number] (issue number), [Page range for whole article]. doi:10.XXXX.XXXXXX Miller, J. M. (2017). Trauma caretaking and compassion fatigue. Trauma Prevention, 14 (2), 243-45. doi: 10.XXXX.XXXXXX |
| Two (Use “&”) |
Books: [Last name], [First initial]. [Middle initial]., & [Last name], [First initial]. [Middle initial]. ([Year]). [Title of book: Capitalize first word of subtitle]. [City, State abbreviation/Country for non-US publications]: [Publisher]. Miller, J. M., & Wallace, R. A. (2017). Epigenetic mechanisms: An overview. Lima, Peru: PublishCo. Journals: [Last name], [First initial]. [Middle initial]., & [Last name], [First initial]. [Middle initial]. ([Year]). [Article title]. [Journal Title], [Volume number] (issue number), [Page range for whole article]. doi:10.XXXX.XXXXXX Miller, J. M., & Wallace, R. A. (2017). Trauma caretaking and compassion fatigue. Trauma Prevention, 14 (2), 243-45. doi: 10.XXXX.XXXXXX |
| Three to seven (Commas separate author names; use “&” before the last author name) |
Books: [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., …, & [Last name], [First initial]. [Middle initial]. ([Year]). [Title of book: Capitalize first word of subtitle]. [City, State Abbreviation/Country for non-US publications]: [Publisher]. Miller, J. M., Wallace, R. A., …, & Johnson, C. T. (2017). Epigenetic mechanisms: An overview. Lima, Peru: PublishCo. Journals: [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., …, [Last name], [First initial]. [Middle initial]. ([Year]). [Article title]. [Journal Title], [Volume number] (issue number), [Page range for whole article]. doi:10.XXXX.XXXXXX Miller, J. M., Wallace, R. A., …, & Johnson, C. T. (2017). Trauma caretaking and compassion fatigue. Trauma Prevention, 14 (2), 243-45. doi: 10.XXXX.XXXXXX |
| More than seven (List the first six authors, then use an ellipsis (…) and list the last author; no “&” before the final author name) |
Books: [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., … [Last name], [First initial]. [Middle initial]. ([Year]). [Title of book: Capitalize first word of subtitle]. [City, State Abbreviation/Country for non-US publications]: [Publisher]. Miller, J. M., Wallace, R. A., Smith, M. T., Lewis, R. V., Higgs, R. Q., Young, D. A., … Johnson, C. T. (2017). Epigenetic mechanisms: An overview. Lima, Peru: PublishCo. Journals: [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., [Last name], [First initial]. [Middle initial]., … [Last name], [First initial]. [Middle initial]. ([Year]). [Article title]. [Journal Title], [Volume number] (issue number), [Page range for whole article]. doi:10.XXXX.XXXXXX Miller, J. M., Wallace, R. A., Smith, M. T., Lewis, R. V., Higgs, R. Q., Young, D. A., … Johnson, C. T. (2017). Trauma caretaking and compassion fatigue. Trauma Prevention, 14 (2), 243-45. doi: 10.XXXX.XXXXXX |
Endnotes and footnotes
The APA style does not use footnotes and strongly discourages the use of endnotes, which should only provide tangential information. However, sometimes content notes are necessary. In such cases, use the notation covered in Section 2.12 of the APA Publication Manual.
In-text or parenthetical citations (author-date system)
The APA style uses the author-date notation, and the in-text citation rules apply to both digital and print editions of books and journals. *Note: The author-number thresholds for changing formatting are different from those for reference lists. Also, while providing page number references is optional for paraphrased statements; the APA recommends citing page numbers.
| Number of authors | Author names mentioned in your statement | Quoting or paraphrasing WITHOUT mentioning author in your statement |
| One | [Last name] ([Year]) has argued that [“Quote”/paraphrased statement] (p. [Page(s) referenced]). Miller (2017) has argued that “quote”/paraphrased statement (p. 14). |
[“Quote”/paraphrased statement] ([Last name], [Year], [Page(s) referenced]). “Quote”/paraphrased statement (Smith, 2017, pp. 23-25). |
| Two (Use “&”) |
[Last name] & [Last name] ([Year]) have argued that [“Quote”/paraphrased statement] (p. [Page(s) referenced]). Miller & Jones (2017) have argued that “quote”/paraphrased Statement (p. 14). |
[“Quote”/paraphrased statement] ([Last name], [Last name], & [Last name], [Year], p. [Page(s) referenced]). “Quote”/paraphrased statement (Smith & Wallace, 2015, p. 34). |
| Three to five (Use “&” for first mention and “et al.” for subsequent references to the same work) |
First mention: [Last name], [Last name], & [Last name] ([Year]) have argued that ["quote"/paraphrased statement] (p. [Page(s) referenced]). Miller, Smith, & Thompson (2017) have argued that “quote”/paraphrased statement (p. 14). Subsequent mentions: [Last name] et al. ([Year]) have argued that ["quote"/paraphrased statement] (p. [Page(s) referenced]). Miller et al. (2017) have argued that “quote”/paraphrased statement (p. 14). |
First mention: ["Quote"/paraphrased statement] ([Last name], [Last name], & [Last name], [Year], p. [Page(s) referenced]). “Quote”/paraphrased statement (Smith, Wallace, & Thompson, 2015, p. 34). Subsequent mentions: ["Quote"/paraphrased statement] ([Last name] et al., [Year], p. [Page(s) referenced]). “Quote”/paraphrased statement (Smith et al., 2015, p. 34). |
| Six or more | [Last name] et al. ([Year]) have argued that ["quote"/paraphrased statement] (p. [Page(s) referenced]). Miller et al. (2017) have argued that “quote”/paraphrased statement (p. 14). |
["Quote"/paraphrased statement] ([Last name] et al. [Year], p. [Page(s) Referenced]). “Quote”/paraphrased statement (Smith et al., 2015, p. 34). |
Chicago style
The Chicago style is commonly used in humanities-focused works. Below, we only comment on general book and journal citation formats. For additional information, click here; see also Chapters 14 and 15 of The Chicago Manual of Style, 16th edition. For an example of an annotated paper that uses bibliographic notation, see Purdue Owl’s NB sampler by clicking here. For an example of an author-date paper, click here. Note that for formally published online sources, such as electronic academic journals, you do not need to include access date information except if required by your publisher or discipline. If no DOI is available, provide the URL. Unlike the APA style, the Chicago style does NOT use the ampersand (&) in name lists; instead, use “and”. Additionally, an author’s given names (first and middle) should be written in full (no initials) unless the author consistently publishes using initials.
Reference lists
Books
| Number of authors | Bibliographic system (humanities) | Author-date system (social, natural, and physical sciences) |
| One | [Last name], [First name(s)]. [Book Title]. [Location]: [Publisher], [Year]. Smith, Mary. Epigenetic Mechanisms. New York: PublishCo, 2017. |
[Last name], [First name(s)]. [Year]. [Book Title]. [Location]: [Publisher]. Smith, Mary. 2017. Epigenetic Mechanisms. New York: PublishCo. |
| Two or more (List ALL authors) |
[Last name], [First name(s)], [First name(s)] [Last name], …, and [First name(s)] [Last name]. [Book Title]. [Location]: [Publisher], [Year]. Smith, Mary T., Mark Allen, Helen Carter, …, and George Turner. Epigenetic Mechanisms. New York: PublishCo, 2017. |
[Last name], [First name(s)], [First name(s)] [Last name], …, and [First name(s)] [Last name]. [Year]. [Book Title]. [Location]: [Publisher]. Smith, Mary T., Mark Allen, Helen Carter, …, and George Turner. 2017. Epigenetic Mechanisms. New York: PublishCo. |
Journals
| Number of authors | Bibliographic system (humanities) | Author-date system (social, natural, and physical sciences) |
| One | Print: [Last name], [First name(s)]. “[Article title].” [Journal Title] [Volume number], no. [Issue number] ([Year]): [Page range for whole article]. Miller, Jack M. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4 (2017): 243-45. Online: [Last name], [First name(s)]. “[Article title].” [Journal Title] [Volume number], no. [Issue number] ([Year]): [Page range for whole article]. Accessed [Month DD, YYYY]. doi: [DOI Number]. Miller, Jack. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4 (2017): 243-45. Accessed June 12, 2017. doi: XX.XXXX/XXXXXX. |
Print: [Last Name], [First Name(s)]. [Year]. “[Article Title].” [Journal Title] [Volume Number], no. [Issue Number]: [Page Range for Whole Article]. Miller, Jack M. 2017. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4: 243-45. Online: [Last Name], [First name(s)]. [Year]. “[Article title].” [Journal Title] [Volume number], no. [Issue number]: [Page range for whole article]. Accessed [Month DD, YYYY]. doi: [DOI Number]. Miller, Jack. 2017. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4: 243-45. Accessed June 12, 2017. doi: XX.XXXX/XXXXXX. |
| More than two (List ALL authors) |
Print: [Last name], [First name(s)], [First name(s)] [Last name], …, and [First name(s)] [Last name]. “[Article title].” [Journal Title] [Volume number], no. [Issue number] ([Year]): [Page range for whole article]. Miller, Jack M., Mary Rogers, …, and David L. Smith. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4 (2017): 243-45. Online: [Last name], [First name(s)], [First name(s)] [Last name], …, and [First name(s)] [Last name]. “[Article title].” [Journal Title] [Volume number], no. [Issue number] ([Year]): [Page range for whole article]. Accessed [Month DD, YYYY]. doi: [DOI number]. Miller, Jack M., Mary Rogers, …, and David L. Smith. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4 (2017): 243-45. Accessed June 12, 2017. doi: XX.XXXX/XXXXXX. |
Print: [Last name], [First name(s)], [First name(s)] [Last name], …, and [First name(s)] [Last name]. [Year]. “[Article title].” [Journal Title] [Volume number], no. [Issue number]: [Page range for whole article]. Miller, Jack M., Mary Rogers, …, and David L. Smith. 2017. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4: 243-45. Online: [Last name], [First name(s)], [First name(s)] [Last name], …, and [First name(s)] [Last name]. [Year]. “[Article title].” [Journal Title] [Volume number], no. [Issue number]: [Page range for whole article]. Accessed [Month DD, YYYY]. doi: [DOI Number].Miller, Jack M., Mary Rogers, …, and David L. Smith. 2017. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention 14, no. 4: 243-45. Accessed June 12, 2017. doi: XX.XXXX/XXXXXX. |
Endnotes and footnotes (bibliographic system)
Books
| Number of authors | Bibliographic system (humanities) |
| One | First mention: [First name(s)] [Last name], [Book Title] ([Location]: [Publisher], [Year]), [Page(s) referenced]. Mary T. Smith, Epigenetic Mechanisms: an Overview (New York: PublishCo, 2017), 23-35. Subsequent mentions: [Last Name], [Shortened book title], [Page(s) referenced]. Smith, Epigenetic Mechanisms, 55. |
| Two to three | First mention: [First name(s)] [Last name], [First name(s)] [Last name], and [First name(s)] [Last name], [Book Title] ([Location]: [Publisher], [Year]), [Page(s) referenced]. Mary T. Smith, Leslie Wilson, and George Turner, Epigenetic Mechanisms: an Overview (New York: PublishCo, 2017), 68-69. Subsequent mentions: [Last name], [Last name], and [Last name], [Shortened Book Title], [Page(s) referenced]. Smith, Wilson, and Turner, Epigenetic Mechanisms, 70-75. |
| Four or more (Use “et al.”) |
First mention: [First name(s)] [Last name] et al., [Book Title] ([Location]: [Publisher], [Year]), [Page(s) referenced]. Mary T. Smith et al., Epigenetic Mechanisms: an Overview (New York: PublishCo, 2017), 23-35. Subsequent mentions: [Last name] et al., [Shortened Book Title], [Page(s) referenced]. Smith et. al, Epigenetic Mechanisms, 55. |
Journals
| Number of authors | Bibliographic system (humanities) |
| One | First mention:
Subsequent mentions (for both print and online): Miller, “Trauma Caretaking,” 244. |
| Two to three | First mention:
Subsequent mentions (for both print and online): Miller, Rogers, and Smith, “Trauma Caretaking,” 244. |
| Four or more (Use “et al.”) |
First mention:
Subsequent mentions (for both print and online): Miller et al., “Trauma Caretaking,” 244. |
In-text or parenthetical citations (author-date system)
Parenthetical citations are more frequently used in the author-date system commonly adopted by social, physical, and natural science professionals. The same notation is used for digital and print editions of books and journals.
| Number of authors | Author names mentioned in your statement | Quoting or paraphrasing WITHOUT mentioning author in your statement |
| One | [Last name] ([Year]) argues that ["quote"/paraphrased statement] ([Page(s) referenced]). Miller (2017) argues that “quote”/paraphrased Statement (14). |
["Quote"/paraphrased statement] ([Last name] [Year], [Page(s) referenced]). “Quote”/paraphrased statement (Smith 2017, 23-25). |
| Two to three | [Last name] and [Last name] ([Year]) argue that ["quote"/paraphrased statement] ([Page(s) referenced]). Miller and Jones (2017) argue that “quote”/paraphrased statement (14). |
["Quote"/paraphrased statement] ([Last name], [Last name], and [Last name] [Year], [Page(s) referenced]). “Quote”/paraphrased statement (Smith, Rogers, and Wallace 2015, 34). |
| Four or more (Use “et al.”) |
[Last name] et al. ([Year]) argue that ["quote"/paraphrased statement] ([Page(s) referenced]). Miller et al. (2017) argue that “quote”/paraphrased statement (14). |
["Quote"/paraphrased statement] ([Last name] et al. [Year], [Page(s) referenced]). “Quote”/paraphrased statement (Smith et al. 2015, 34). |
MLA style
The MLA style is commonly used by humanities professionals. General book and journal citation formations are highlighted below. For information regarding other media and special cases, see the MLA Handbook (8th ed.).
Reference lists (works cited page)
| Number of authors | Books | Journals |
| One | [Last name], [First name] [Middle initial]. [Book Title]. [Publisher], [Year]. Smith, Mary T. Epigenetic Mechanisms: an Overview. PublishCo, 2017. |
Print: [Last name], [First name]. “[Article title].” [Journal Title], vol. [Volume], no. [Issue], [Date], pp. [Pages]. Miller, Jack. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention, vol. 14, no. 4, 2017, pp. 243-45. Online: [Last name], [First name]. “[Article title].” [Journal Title], vol. [Volume], no. [Issue], [Date], pp. [Pages]. [Electronic database], doi: [DOI number]. Accessed [DD MM YYYY]. Miller, Jack. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention, vol. 14, no. 4, 2017, pp. 243-45. JournalDatabase, doi: XX.XXXX/XXXXXX. Accessed 19 June 2017. |
| Two | [Last name], [First name] and [First name] [Last name]. [Book Title]. [Publisher], [Year]. Smith, Mary T., and George Thompson. Epigenetic Mechanisms: an Overview. PublishCo, 2017. |
Print: [Last name], [First name] and [First name] [Last name]. “[Article title].” [Journal Title], vol. [Volume], no. [Issue], [Year], pp. [Pages]. Miller, Jack, and George Thompson. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention, vol. 14, no. 4, 2017, pp. 243-45. Online: [Last name], [First name] and [First name] [Last name]. “[Article title].” [Journal Title], vol. [Volume], no. [Issue], [Year], pp. [Pages]. [Electronic database], doi: [DOI number]. Accessed [DD MM YYYY]. Miller, Jack, and George Thompson. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention, vol. 14, no. 4, 2017, pp. 243-45. JournalDatabase, doi: XX.XXXX/XXXXXX. Accessed 19 June 2017. |
| Three or more | [Last name], [First name], et al. [Book Title]. [Publisher], [Year]. Smith, Mary T., et al. Epigenetic Mechanisms: an Overview. PublishCo, 2017. |
Print: [Last name], [First name], et al. “[Article title].” [Journal Title], vol. [Volume], no. [Issue], [Year], pp. [Pages]. Miller, Jack, et al. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention, vol. 14, no. 4, 2017, pp. 243-45. Online: [Last name], [First name], et al. “[Article title].” [Journal Title], vol. [Volume], no. [Issue], [Year], pp. [Pages]. [Electronic database], doi: [DOI number]. Accessed [DD MM YYYY]. Miller, Jack, et al. “Trauma Caretaking and Compassion Fatigue.” Trauma Prevention, vol. 14, no. 4, 2017, pp. 243-45. JournalDatabase, doi: XX.XXXX/XXXXXX. Accessed 19 June 2017. |
Endnotes and footnotes
The MLA style does not generally encourage endnotes and footnotes; however, it does accommodate their use when needed to clarify points that don’t otherwise belong in the main body of your work. The formats for these notes are similar to the format used in in-text citations (described further below), but without the parentheses:
- See [last name] [page range].
See Miller 153-45.
- See [last name], especially [page range], for [content topic].
See Miller, especially 64-68, for additional information about this phenomenon.
- Regarding [content topic], see [last name] [page range] and [last name] [page range]; for [content topic], see [last name] [page range], [last name] [page range], and [last name] [page range].
Regarding this phenomenon’s impact on trauma caretakers, see Miller 54-68 and Willis 23-25; for alternative explanations, see Jones 23-25, Thompson 64-55, and Smith 12-15.
- [Comment]. See [last name] [page range], [last name] [page range], [last name] [page range].
Other interview-based studies were conducted on trauma victim caretakers. See Miller 12-45, Thompson 63-69, and Jones 5-8.
In-text (parenthetical)
The MLA style uses an author-page style instead of an author-date style.
| Number of authors | Author names mentioned in your statement | Quoting or paraphrasing WITHOUT mentioning author in your statement |
| One | [Last name] argues that ["quote"/paraphrased statement] ([Page(s) referenced]). Miller argues that “quote”/paraphrased statement (14). |
["Quote"/paraphrased statement] ([Last name] [Page(s) Referenced]). “Quote”/paraphrased statement (Smith 23-25). |
| Two (Use “and”) |
[Last name] and [Last name] argue that ["quote"/paraphrased statement] ([Page(s) referenced]). Miller and Jones argue that “quote”/paraphrased statement (14). |
["Quote"/paraphrased statement] ([Last name] and [Last name] [Page(s) referenced]). “Quote”/paraphrased statement (Smith and Wallace 34). |
| Three or more (Use “et al.”) |
[Last name] et al. argue that ["quote"/paraphrased statement] ([Page(s) referenced]). Miller et al. argue that “quote”/paraphrased statement (14). |
["Quote"/paraphrased statement] ([Last name] et al. [Page(s) referenced]). “Quote”/paraphrased statement (Smith et al. 34). |
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