Citation Styles by Discipline: STEM

STEM fields use a range of discipline-specific styles like ACM (Association for Computing Machinery), ACS (American Chemical Society), CSE (Council of Science Editors), and IEEE (Institute of Electrical and Electronics Engineers), as well as APA. 

ACM style uses in-text, parenthetical citations in brackets (example: [Smith 2020]) or numerical footnotes (example: [1] [3]) and full bibliographic references, listed in a Reference list:

1. Authors: List authors names in regular order (example: John Smith and Jane Doe), followed by a period. Alphabetize entries based on lead authors' last names if using author-date system. List in order of citation if using numerical footnotes.
2. Title of article: Write out the title, capitalizing only the first letter and proper nouns.
3. Title of journal or conference proceedings: Include "In" and then the title of the journal. Italicize the title.
4. Volume and issue number: Next, include the volume and issue number of the journal, separated by a comma, for journal articles.
5. Date: Include a date range of the conference for conference proceedings (example: September 15-16, 2016). For journal articles, include the publication date in parentheses (Aug. 2021). 
6. Location and conference name: For conference proceedings, also include the location of the conference and its name, separated by commas (example: Ann Arbor, Michigan. IEEE,).
7. Page range: For both journal articles and conference proceedings, include the page range for the piece, followed by a period.
8. DOI: For sources with a DOI, write DOI, followed by a colon, and then include the DOI. DO NOT end the entry with a period.

In the ACS style, you can cite references in three ways:

1. By superscript numbers, which appear outside the punctuation if the citation applies to a whole sentence or clause.
2. By italic numbers in parentheses on the line of text and inside the punctuation.
3. By author name and year of publication in parentheses inside the punctuation (known as author-date).

The reference list appears at the end of the paper in numerical order if cited by number of in alphabetical order if cited by author-date. A reference list must include certain minimum data:

• Journal references must include author names, abbreviated journal title, year of publication, volume number, and initial page of cited article (the complete span is better)
• Book references must include author or editor names, book title, publisher, city of publication, year of publication
• For material other than books and journals, sufficient information must be provided so that the source can be identified and located

In lists, references always end with a period. Use only the initials of the authors' given names and use full stops and spaces between the initials. Last name comes first. Include all author names in a reference citation. With multiple authors, separate the names from one another by semicolons.

CSE style has three systems to cite sources:

• Name-Year (N-Y) system: Author name and year of the publication are placed in parentheses in the text (e.g. Rode 2012). The reference list is ordered alphabetically by author name.
• Citation-Name (C-N) system: Superscript numbers are used to identify in-text citations. In the alphabetized reference list, each numeral corresponds with a unique reference.
• Citation-Sequence (C-S) system: Superscript numbers are used to identify in-text citations. In the reference list, sources are numbered sequentially by the order in which they appear in the text (the difference to the C-N system is that they might not be in alphabetical order by author).

It is not necessary to cite sources in-text. Instead, refer to the source with a number in a square bracket.

The square brackets correspond to appropriate sources in the reference list. Place the bracketed citations within the line of text, before any punctuation, with a space before the first bracket. The in-text citation numbers start at [1] and continue in ascending order throughout the paper. If you are referring to a source you have already cited in your paper, use the previously assigned number.

Use et al. when three or more names are given for a reference cited in the text.

A numbered reference list must be provided at the end of your paper, containing the full details of all the sources you have cited in your text. All references must be listed numerically in the order they have been cited in your text, beginning with [1], and ascending. Include the bracketed number. Reference list entries do not follow an alphabetical order by author or title of sources, in contrast to many other citation styles.

The title of your reference list should simply be 'References' and either centered or aligned left at the top of the page. Each reference in the list should be a hanging indent. The bracketed number should align with the left side of the page. Author's name are listed as first initial, last name. Journal or book titles are listed in italics.

What Citation Style to Use for Computer Science 
This article outlines the most popular citation styles in computer science.

What Citation Style to Use for Science 
This guide offers advice on what citation styles are most common in science fields.

ACM Citation Style 
This resource is from the official site of the ACM.

Computer Science Research Guide 
This guide offers examples for multiple source types in ACM and other common styles.

ACS Citation Style 
This resource covers the basics of ACS style and includes a citation generator for creating quick, accurate citations.

ACS Guide 
This is the official site and guide for ACS style.

CSE Citation Style 
This guide offers information on CSE style, as well as examples.

CSE Style Overview 
This resource provides a basic overview of CSE style.

How to Format Your References in IEEE Style 
This resource features numerous example references in IEEE style for a variety of source types.

IEEE Reference Guide 
This PDF includes the official reference guide for IEEE style.

Purdue OWL IEEE Guide 
The Purdue OWL features a guide devoted to IEEE and includes examples.