Citation Style Guide

Master the major citation styles (APA, MLA, Chicago, IEEE, Vancouver) with examples, reference manager configuration, and CSL customization.

Citation Style Overview

Style	Primary Discipline	In-Text Format	Reference List Name
APA 7th	Psychology, social sciences, education	(Author, Year)	References
MLA 9th	Humanities, literature, languages	(Author Page)	Works Cited
Chicago (Author-Date)	Social sciences, natural sciences	(Author Year)	References
Chicago (Notes-Bib)	History, arts, humanities	Footnotes/endnotes	Bibliography
IEEE	Engineering, computer science	[1] numbered	References
Vancouver	Medicine, biomedical sciences	(1) numbered	References
Harvard	General, UK/Australia universities	(Author Year)	Reference List
Nature	Multidisciplinary sciences	Superscript numbered	References

APA 7th Edition

In-Text Citations

One author:     (Smith, 2023)     or   Smith (2023) found that...
Two authors:    (Smith & Jones, 2023)
3+ authors:     (Smith et al., 2023)
Direct quote:   (Smith, 2023, p. 45)
Multiple works: (Jones, 2021; Smith, 2023)
Same author, same year: (Smith, 2023a, 2023b)
Organization:   (World Health Organization [WHO], 2023)
                then subsequent: (WHO, 2023)

Reference List Examples

# Journal article
Smith, J. A., & Jones, B. C. (2023). Title of the article in sentence
    case. Journal Name in Title Case, 45(2), 123-145.
    https://doi.org/10.1234/example

# Book
Williams, R. T. (2022). Title of the book in sentence case (3rd ed.).
    Publisher Name. https://doi.org/10.1234/example

# Chapter in edited book
Chen, L. (2023). Chapter title. In A. Editor & B. Editor (Eds.),
    Book title (pp. 50-75). Publisher. https://doi.org/10.1234/example

# Conference paper
Lee, S., & Park, J. (2023). Paper title. In Proceedings of the 2023
    Conference Name (pp. 100-110). Publisher.
    https://doi.org/10.1234/example

# Webpage
National Institutes of Health. (2023, March 15). Page title.
    https://www.nih.gov/example

# Preprint
Garcia, M. (2023). Title of preprint. arXiv.
    https://doi.org/10.48550/arXiv.2301.12345

# Dataset
Johnson, K. (2023). Dataset title (Version 2.0) [Data set]. Repository.
    https://doi.org/10.1234/example

MLA 9th Edition

In-Text Citations

One author:     (Smith 45)         or   Smith argues that "..." (45).
Two authors:    (Smith and Jones 45)
3+ authors:     (Smith et al. 45)
No page number: (Smith)
Multiple works: (Smith 45; Jones 67)

Works Cited Examples

# Journal article
Smith, John A., and Beth C. Jones. "Article Title in Title Case."
    Journal Name, vol. 45, no. 2, 2023, pp. 123-45.
    https://doi.org/10.1234/example.

# Book
Williams, Rose T. Title of Book in Italics. 3rd ed., Publisher, 2022.

# Chapter in edited book
Chen, Li. "Chapter Title." Book Title, edited by Amy Editor and
    Bob Editor, Publisher, 2023, pp. 50-75.

# Website
"Page Title." Site Name, Organization, 15 Mar. 2023,
    www.example.com/page.

IEEE Style

In-Text Citations

IEEE uses numbered references in square brackets, in order of first appearance:

As shown in [1], deep learning has achieved...
Several studies [2]-[5] have demonstrated...
Smith et al. [6] proposed...

Reference List Examples

# Journal article
[1] J. A. Smith and B. C. Jones, "Article title in sentence case,"
    J. Name Abbreviated, vol. 45, no. 2, pp. 123-145, Feb. 2023,
    doi: 10.1234/example.

# Conference paper
[2] S. Lee and J. Park, "Paper title," in Proc. Conf. Name,
    City, Country, 2023, pp. 100-110.

# Book
[3] R. T. Williams, Book Title in Italics, 3rd ed. City, Country:
    Publisher, 2022.

# Online source
[4] Author, "Page title," Website, date. [Online]. Available:
    https://www.example.com

Using CSL (Citation Style Language)

CSL is the standard format used by Zotero, Mendeley, and other reference managers to define citation styles. Over 10,000 CSL styles are available at github.com/citation-style-language/styles.

Installing a CSL Style in Zotero

1. Visit the Zotero Style Repository: zotero.org/styles
2. Search for your target journal or style (e.g., "Nature", "APA 7th")
3. Click to install directly into Zotero
4. In Zotero, go to Settings > Cite > Styles to manage installed styles

CSL Style Structure

<?xml version="1.0" encoding="utf-8"?>
<style xmlns="http://purl.org/net/xbiblio/csl" class="in-text" version="1.0">
  <info>
    <title>Custom Style</title>
    <id>http://www.example.com/custom-style</id>
  </info>

  <!-- How in-text citations appear -->
  <citation>
    <sort>
      <key variable="author"/>
      <key variable="issued"/>
    </sort>
    <layout prefix="(" suffix=")" delimiter="; ">
      <group delimiter=", ">
        <names variable="author">
          <name form="short" and="symbol"/>
        </names>
        <date variable="issued" form="text" date-parts="year"/>
      </group>
    </layout>
  </citation>

  <!-- How the bibliography/reference list appears -->
  <bibliography>
    <sort>
      <key variable="author"/>
      <key variable="issued"/>
    </sort>
    <layout>
      <!-- Define reference formatting here -->
    </layout>
  </bibliography>
</style>

BibTeX Entry Types

For LaTeX users, correct entry types ensure proper formatting:

@article{smith2023,
  author  = {Smith, John A. and Jones, Beth C.},
  title   = {Article Title},
  journal = {Journal Name},
  year    = {2023},
  volume  = {45},
  number  = {2},
  pages   = {123--145},
  doi     = {10.1234/example}
}

@inproceedings{lee2023,
  author    = {Lee, Sam and Park, Jin},
  title     = {Paper Title},
  booktitle = {Proceedings of the 2023 Conference},
  year      = {2023},
  pages     = {100--110},
  doi       = {10.1234/example}
}

@book{williams2022,
  author    = {Williams, Rose T.},
  title     = {Book Title},
  edition   = {3rd},
  publisher = {Publisher Name},
  year      = {2022}
}

@misc{garcia2023preprint,
  author = {Garcia, Maria},
  title  = {Title of Preprint},
  year   = {2023},
  eprint = {2301.12345},
  archiveprefix = {arXiv},
  primaryclass  = {cs.CL}
}

Quick Decision Guide

If your field is...	Use this style	LaTeX bibliography style
Psychology, education	APA 7th	apacite or biblatex-apa
Literature, languages	MLA 9th	biblatex-mla
History, arts	Chicago Notes	chicago-authordate
Engineering, CS (IEEE venues)	IEEE	IEEEtran
Medicine, clinical	Vancouver	vancouver
Natural sciences (Nature group)	Nature	naturemag
Economics	Chicago Author-Date	chicago-authordate
Check specific journal	Journal's author guidelines	See journal website