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ACS - Referencing Guide

Citing in the Text

Citing in the Text

Indicating the Relevant Reference in the Text

A number in superscript format, placed in the text of the essay, indicates the relevant reference.

The superscript number appears outside the punctuation if the citation applies to a whole sentence or clause. 

If an author's name is mentioned in the text, place the citation number in a logical place within the sentence as close as possible to the author's name.

Citations are numbered consecutively in the order in which they appear in the text and each citation corresponds to a numbered reference containing publication information about the source cited in the reference list at the end of the publication, essay or assignment.

Once a source has been cited, the same number is used in all subsequent references.

No distinction is made between print and electronic references when citing within the text.

  Here are some examples of this kind of referencing:

The largest lesion in the first study was 10 cm.13
The theory was first put forward in 1987.1
Scholtz2 has argued that...
Several recent studies3,4,15,16 have suggested that...
For example, see7.

Citing More Than One Reference at a Time

When citing more than one source at a time, list the numbers in ascending order and separate them by commas without spaces. If they are part of a consecutive series, use a hyphen to indicate a range of three or more:



Use quotation marks to enclose short direct quotations of up to 50 words:

In the book Megatrends, Naisbett concludes, "We are moving from the specialist who is soon obsolete to the generalist who can adapt."3

Use a narrower column width, indented on both sides, for longer quotations of 50 words or more. Do not use quotation marks:

In the late 1890s, the Scottish chemist Sir William Ramsay discovered the elements helium, neon, argon, krypton, and xenon. These elements, along with radon, were placed in group VIIIA of the periodic table and nicknamed inert (or noble) gases because of their tendency not to react with other elements. The tendency of the noble gases to not react with other elements has to do with their electron configurations. All of the noble gases have full valence shells; this configuration is a stable configuration and one that other elements try to achieve by reacting together. In other words, the reason atoms react with each other is to reach a state in which their valence shell is filled.4

See the All Examples page for examples of in-text and reference list entries for specific resources such as articles, books and web pages.