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ACS (American Chemical Society) Citation Style Guide

General guidelines to ACS citation format

In-Text Citations

There are three ways to format an in-text citation using ACS. All three are acceptable, but it is important to pick one and use it throughout your paper. Do not use multiple formats in the same paper. The formats are: 

  • Superscript numbers: These numbers will appear small and outside the punctuation of the sentence. ​1
  • Italic numbers: These will go inside parenthesis and before the punctuation ending the sentence (2). 
  • Author name and year: These will be inside parenthesis and before the punctuation mark (King et al., 2018).

If you use either of the numbered formats, the citations should be numbered sequentially in your paper. The reference section of your paper should be in numerical order, so that "2" in the body of your paper corresponds to "2" in your reference list. If you use the author name and year format, the citations in your reference section should be alphabetized by authors' last names.