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Citation

About ACS

This guide provides a brief introduction to American Chemical Society (ACS) Style and supporting resources. For more additional examples of ACS references and citations, please consult the ACS Style Quick Guide or The ACS Style Guide in our Reference Collection.

In-Text Citations

A reference consists of two main components:

  1. an "in-text citation" that appears in the text of your writing, and
  2. a detailed "reference" that appears in your list of sources at the end of your document.

When you reference another source in the body of your paper, use an in-text citation. This gives credit to the original source of an idea and refers to the reference in your bibliography at the end of your document.

Your instructor may ask you to form in-text citation by authors' names or by number. Always check with your instructor to confirm which convention your class is using.

Also known as Author-Date, citing by name requires the inclusion of the author or authors' name and the date of publication. References at the end of your document should then be arranged alphabetically by the author's last name.

Basic Format:

(Author's Last Name(s) or Organization, Year)

(Morelli and Scholkmann, 2023)

I am...

In ACS Style, it is preferred that you paraphrase and summarize from a research article rather than quoting the author's words directly. Always include the last name of the author(s) and the year of the publication, so your reader can find the full citation in the reference list.

According to Morelli and Scholkmann (2023), the role of lipids in oxygen absorbtion is critical for many aerobic species. Further, each species' gas exchange system has evolved to meet specific environmental, anatomical, and physiological needs (Jürgens and Gross, 2002).

If you're quoting the exact words of someone else, introduce the quote with an in-text citation in parentheses. Any sentence punctuation (e.g. commas, periods, etc.) should be placed outside the quotation marks or after the in-text citation unless included in the original quotation.

  • According to Morelli and Scholkmann (2023), "Direct quote".
  • Jürgens and Gross (2002) found that "Direct quote".
  • [Some other introduction] "Direct quote" (Brown 2019).

Note: The ACS Style Guide does not provide specific guidelines for identifying or including page numbers in in-text citations. However, a specific journal or your instructor may require the inclusion of page numbers when directly quoting from a source. Always confirm with your instructor before submitting your work.


When citing a passage longer than three sentences or 50 words, use a block quote

  • Block quotes do not need quotation marks and should be indented from the left margin.
  • If the text preceding the excerpt does not include an in text citation, then the citation should be included at the end of the block quote after the closing punctuation.

Morelli and Scholkmann (2023) contend:

It seems unlikely that the way developed during evolution to accomplish the adjustment of ATP production to neuronal activity is the detour of first increasing CBF, which then ‘passively' drives an increased ATP production by increased oxygen delivery. Such a regulation would introduce a high vulnerability of brain function depending totally on intact neurovascular coupling.

Toro Tip: Use direct quotes sparingly! Focus on summarizing the findings from multiple research studies. In the sciences, only use the exact phrasing or argument of an individual when necessary.

 

In-text citations differ depending on the number of authors listed for a work, and if there is a group author.

I'm citing a work with...

You only need the author's last name and the year in parentheses. Separate with a comma.

(Abrams, 2018)

List both authors' last names, connected with 'and,' and the year. Separate the authors' names from the year with a comma.

(Wegener and Petty, 1994)

If there are more than two authors use et al., which means "and others," a comma and the year.

(Harris et al., 2018)

Groups or organizations may be the author of a resource. Acronyms for well-known organizations may be used. Otherwise, the full name of an organization should be used. Regardless, the in-text citation author should match the end reference.

(Centers for Disease Control and Prevention, 2013)

or

(CDC, 2013)

You may be asked to cite using a numerical convention where you refer to items in your bibliography either by using a number within parentheses (1) or in superscript1

If using this format, references in your bibliography are number sequentially.  If a reference is repeated, use the original number rather than giving it a new number.

In-Text Citation:

The role of lipids in oxygen absorption is critical for many aerobic species.1 Further, each species' gas exchange system has evolved to meet specific environmental, anatomical, and physiological needs.2
The role of lipids in oxygen absorption is critical for many aerobic species (1). Further, each species' gas exchange system has evolved to meet specific environmental, anatomical, and physiological needs (2).

References:

1. Morelli AM, Scholkmann F. The significance of lipids for the absorption and release of oxygen in biological organisms. Adv Exp Med Biol. 2023;1438:93-99. https://doi.org/10.1007/978-3-031-42003-0_16
2. Jurgens KD, Gross G. Phylogeny of gas exchange systems. AINS. 2002;37(4):185-195. https://doi.org/10.1055/s-2002-25080

References

Include the complete citation at the end of your paper in a References section. References in Citation-Name and Name-Year systems are organized by the author's last name in alphabetic (A-Z) order. References in Citation-Sequence systems should appear in the order of assigned superscript number. Use an hanging indent to separate each list item.

I'm citing a...

  1. Author(s). Note: List each author's last name and initials as Author, A. A.; Author, B. B.; Author, C. C. No need to place an ampersand (&) or "and" before the final author's name. Generally, all authors should be listed; however, a journal or your instructor may prefer you to list the first 10 authors followed by a semicolon and "et al."
  2. Title of the Article. Note: Capitalize the main words of an article's title.
  3. Title of the Journal. Note: Should be italicized.  Abbreviate journal titles longer than one word according to the Chemical Abstracts Service Source Index.
  4. Year of Publication, Note: the year of publication should be bold and followed by a comma.
  5. Volume Note: Should be italicized.
  6. (Issue): Note: If each issue of the journal begin on page 1, include the issue numbers in parentheses. Separate the volume and issue numbers with a space.
  7. Page range. Replace with article number when a publication uses article numbering rather than page numbering.
  8. DOI (Digital Object Identifier) Note: should not be formatted as a hyperlink. See formatting in example below.

Roppongi, T; Mizuno, N; Miyagawa, Y; Kobayashi, T; Nakagawa, K; Adachi, S. Solubility and Mass Transfer Coefficient of Oxygen Through Gas- and Water-Lipid Interfaces. J. Food Sci. 2021, 86 (3), 867–873. DOI: 10.1111/1750-3841.15641

  1. Author(s). Note: List each author's last name and initials as Author, A. A.; Author, B. B.; Author, C. C.
  2. Title of the article. Note: Capitalize the main words of an article's title.
  3. Title of the Newspaper or Publication (location), Note: Capitalize each main word in the publication title and italicize. Include the location of publication in parentheses if available.
  4. Month Day, Year,
  5. updated Month Day, Year. Note: If an article has been updated, include the date in the reference.
  6. Page range or article number. Note: If there is a page range or an article number, conclude the preceding date elements with a comma and conclude the page number element with a period.
  7. URL. Note: If citing an online article from the open web, include the complete URL. If you are citing an article from a database, include the permalink.
  8. (accessed  YYYY-MM-DD). Note: If accessed from a database, include "from" and the database name in the parentheses after the date.

Online Publication:

Kenkel, C. D. Want to See Coral Reefs Grow? Freeze Them. The New York Times (New York, NY), August 15, 2024, updated August 15, 2024. https://www.nytimes.com/2024/08/15/opinion/caribbean-coral-reefs-climate-change.html (accessed 2024-08-19).

Online Publication (Accessed through database):

Kenkel, C. D. Want to See Coral Reefs Grow? Freeze Them. The New York Times (New York, NY), August 15, 2024, updated August 15, 2024, A19. http://libproxy.csudh.edu/login?url=https://www.proquest.com/newspapers/want-see-coral-reefs-grow-freeze-them/docview/3093731911/se-2?accountid=10347 (accessed 2024-08-19 from ProQuest News & Newspapers).

It's important to identify whether you are citing an authored book or an edited book.  If the book maintains the same author(s) throughout the whole book, it should be cited as an authored book.

  1. Author(s). Note: List each author's last name and initials as Author, A. A.; Author, B. B.; Author, C. C.
  2. Chapter Title. Note: Online include a chapter title if citing a single chapter. Conclude with a period and include "In" before the title.
  3. Title of the Book, edition number; Note: Use title case and italicize. Include the edition number (in ordinal form) and the abbreviation "ed." if available.
  4. Series information and/or Volume no.; Note: Include if available. Abbreviate "Volume" as "Vol."
  5. Publisher, Note: If the author is also the publisher, omit the publisher element. Place of publication is not essential.
  6. Year of publication;
  7. Page range. Note: Include if applicable, following the format: pp xx-xx.
  8. DOI (Digital Object Identifier) Note: if citing an eBook.

Authored Whole Book Reference:

Russel, K.; Sheppard, C. Coral Reefs: A Natural History; Princeton University Press, 2021.

Russel, K.; Sheppard, C. Coral Reefs: A Natural History; Princeton University Press, 2021. DOI: 10.2307/j.ctv1h9dh6q

Authored Book Chapter Reference:

Russel, K.; Sheppard, C. Different Kinds of Reefs. In Coral Reefs: A Natural History; Princeton University Press, 2021; pp 60-95.

Russel, K.; Sheppard, C. Different Kinds of Reefs. In Coral Reefs: A Natural History; Princeton University Press, 2021; pp 60-95. DOI: 10.2307/j.ctv1h9dh6q.6

If the book's chapters are written by different authors and was compiled by editors, then it should be cited as an edited book.

  1. Author(s). Note: List each author's last name and initials as Author, A. A.; Author, B. B.; Author, C. C. If citing a whole edited book, the author(s) element may be omitted.
  2. Chapter Title.
  3. In Title of the Book, edition number; Note: Use title case and italicize. Include the edition number (in ordinal form) and the abbreviation "ed." if available.
  4. Editors, Eds.; Note: List each editor's last name and initials as Editor, A. A., Editor, B. B., Author, C. C. Conclude the editors element with with a comma after the last editor initial, "Eds." and a semi-colon.
  5. Series information and/or Volume no.; Note: Include if available. Abbreviate "Volume" as "Vol."
  6. Publisher,
  7. Year of publication;
  8. Page range. Note: Note: Include if applicable, following the format: pp xx-xx.
  9. DOI (Digital Object Identifier) Note: if citing an eBook.

Whole Edited Book Reference:

Biodiversity and Climate Change: Transforming The Biosphere; Lovejoy, T. E., Lee, H., Eds.; Yale University Press, 2021.

 Chapter in an Edited Book Reference:

Parmesan, C. Range and Abundance Changes. In Biodiversity and Climate Change: Transforming the Biosphere; Lovejoy, T. E., Lee, H., Eds.; Yale University Press, 2021; pp 25-38.

  1. Author(s). Note: List each author's last name and initials as Author, A. A.; Author, B. B.; Author, C. C. If there is no individual author, you may use the organization or title of web site in the authors' place.
  2. Title of Webpage, Note: Use the title present on the page. Add the words "Home Page" for additional clarification as needed.
  3. Year.
  4. Title of Web site. Note: Omit if included in author element.
  5. URL
  6. (accessed  YYYY-MM-DD).

Reference:

U.S. Environmental Protection Agency. Basics of Climate Change. https://www.epa.gov/climatechange-science/basics-climate-change (accessed 2024-08-19).

  1. Author(s). Note: List each author's last name and initials as Author, A. A.; Author, B. B.; Author, C. C.
  2. Title of the Report or Bulletin; Note: Capitalize each main word in the title and italicize.
  3. Technical Report or Bulletin Number;
  4. Publishing Organization:
  5. Location,
  6. Date of Publication. Note: if a page range is available, conclude with a semi-colon rather than a period.
  7. Page range. Note: Include if applicable, following the format: pp xx-xx.
  8. URL
  9. (accessed  YYYY-MM-DD).

Reference:

Bishop, R.; Erdman, M. M.; Fields, P.; Fullerton, K.; Jackson, K.; Mahon, B.; National Enteric Disease Surveillance: Salmonella Surveillance Overview; Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases: Atlanta, GA, 2011. https://www.cdc.gov/nationalsurveillance/PDFs/NationalSalmSurveillOverview_508.pdf (accessed 2024-08-19).

  1. Author. Note: List the author's last name and initials as Author, A. A. There is usually only one author for a thesis or dissertation, you don't need to include any faculty advisers.
  2. Title. Note: Capitalize each main word in the title.
  3. Level of Thesis, Note: "Thesis" typically refers to master's-level work, while "dissertation" usually refers to doctoral-level work. The language in the reference should match the language present in the thesis or dissertation.
  4. Degree-Granting University,
  5. Location of University, Note: Include the city and state or city and country. Use two-letter abbreviations for states and spell out countries unless they have standard abbreviations, such as U.K. for United Kingdom.
  6. Date of Completion.
  7. URL Note: Include If accessed online.
  8. (accessed  YYYY-MM-DD). Note: Include if accessed online.

Thesis or Dissertation (accessed online)

Valentin, E. R. Narcissism Predicted by Snapchat Selfie Sharing, Filter Usage, and Editing. M.A. Thesis, California State University Dominguez Hills, Carson, CA, 2019. https://scholarworks.calstate.edu/concern/theses/3197xm925?locale=en (accessed 2024-08-19).

Thesis or Dissertation (in print)

Valentin, E. R. Narcissism Predicted by Snapchat Selfie Sharing, Filter Usage, and Editing. M.A. Thesis, California State University Dominguez Hills, Carson, CA, 2019.

Formatting Tips

How do I make a hanging indent in Word?

1. Highlight the citaiton with your cursor. 

2. Right click. 

3. Select Paragraph.

4. Under Indentation, select Special and Hanging.

Animated gif of creating a hanging indent in Word. Highlight the full citation. Right click. Go to Paragraph. To to the Special drop down menu, select Hanging. Select Okay.

How can I save time formatting my paper? 

Microsoft Word and Google Docs have a Format Painter tool that will copy and apply basic formatting to any text! 

1. Highlight the formatting you want to apply. 

2. Select Format Painter

3. Highlight the text you want to change. 

Note: If using the Format Painter on the Reference List, you'll need to go back and add italics. 

Animated gif of using the Format Painter tool in Word.

Creative Commons License CC by NC 4.0 This guide was created by Aric Haas at CSUDH Library and licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.