An in-text citation is the short signal inside your sentence that tells readers where an idea came from. If the reference list is the shelf, the in-text citation is the label that points to one spot on it. The two always travel together: every source cited in the text must appear in the reference list, and every entry in the list must be cited somewhere in the text.
This guide explains the logic that sits under every style. To generate the actual citation strings, use the in-text citation generator.
Parenthetical vs. narrative citations
- Parenthetical: author and date go in parentheses, usually at the end of the sentence: Online classes raised submission rates (Kim & Lee, 2021).
- Narrative: the author becomes part of the sentence and only the date goes in parentheses: Kim and Lee (2021) reported that online classes raised submission rates.
Both carry the same information. Use parenthetical citations when the finding matters most and narrative citations when who said it matters. In APA, two authors are joined with an ampersand inside parentheses and with "and" in running text. MLA uses "and" in both places. Never name the author twice, once in the sentence and again in the parentheses.
Four citation systems
| System | In the text | Typical styles | Reference list order |
|---|---|---|---|
| Author-date | (Kim, 2021) | APA, Chicago author-date, Korean social science | Alphabetical |
| Author-page | (Kim 45) | MLA | Alphabetical |
| Numeric | [1] or superscript ¹ | IEEE, Vancouver | Order of first citation |
| Notes | Superscript number + footnote | Chicago notes-bibliography, Korean humanities | Bibliography alphabetical |
Author-date suits fields where recency matters. Author-page suits literature and languages, where you keep pointing at particular passages; MLA puts no comma between name and page: (Baron 194). Numeric systems number sources in the order they first appear and reuse that number every time the same source returns. Notes put the full details at the foot of the page, and Chicago recommends shortened notes (surname, short title, page) after the first citation.
Direct quotation and paraphrase
A direct quotation reproduces the original wording. Put it in quotation marks and always give a location:
- APA: (Kim, 2021, p. 45) or pp. 45–46 for a range
- MLA: (Kim 45)
- Chicago author-date: (Kim 2021, 45), with no comma between author and year
- IEEE: [3, p. 45]
APA sets quotations of 40 words or more as block quotations without quotation marks. Many universities set their own threshold for theses, so check the local rules.
A paraphrase restates the idea in your own words. It needs a citation just as much as a quotation does. APA does not require a page number for a paraphrase but encourages one when it helps readers find a passage in a long work.
Swapping a few words while keeping the original sentence structure is patchwriting, and it can be treated as plagiarism. Close the source, write from memory, then compare.
Secondary sources
When you rely on a work you did not read yourself, cite it through the source you did read, and only when the original is truly unavailable.
- APA: name the original and add "as cited in" plus the source you read, with the original year if known: (Rabbitt, 1982, as cited in Lyon et al., 2014). Only Lyon et al. goes in the reference list.
- MLA: use "qtd. in": (qtd. in Smith 12).
- Chicago: give the original in the note, followed by "quoted in" and the source you consulted.
- Korean journals: add "재인용" (secondary citation) with the source you actually read, e.g. 홍길동(1990; 김철수, 2005에서 재인용). Punctuation varies by society.
Listing the original as if you had read it misrepresents your research, and any error in the secondary source becomes your error.
Citing several sources at once
- APA: alphabetical by first author, separated by semicolons: (Adams et al., 2019; Shumway & Shulman, 2015; Westinghouse, 2017). Same author, several years: (Coutlee, 2019, 2020).
- MLA: separate with semicolons; the order is up to you.
- IEEE: the current IEEE Reference Guide writes every number out, "[1], [2], [3], [4]", instead of a dash range such as "[1]–[4]". Older papers used ranges, so follow the venue's template.
- Vancouver: consecutive numbers are usually collapsed into ranges (1–3, 5). Brackets, parentheses or superscripts depend on the journal.
- Korean author-date styles: Korean-language sources often come first in Korean alphabetical order, followed by foreign sources in Latin alphabetical order.
Locators beyond page numbers
| Source | Locator |
|---|---|
| Print book or article | p. 45 / pp. 45–46 (APA), 45 (MLA, Chicago) |
| Web page without pages | para. 3, or a section heading plus paragraph |
| Video or podcast | timestamp 00:12:30 |
| Play or poem | act, scene, line (MLA 1.2.34) |
| Numeric styles | [3, p. 5], [3, Fig. 1], [3, Ch. 2] (IEEE) |
For e-books whose pagination changes with the device, use chapter or section numbers. Reader "location" numbers cannot be reproduced by others, so most styles advise against them.
When missing citations become plagiarism
- Copying sentences without quotation marks, even with a citation attached
- Paraphrasing someone's idea, framework or hypothesis without credit
- Reusing tables, figures or data without attribution
- Reusing your own published text without disclosure (self-plagiarism)
- Presenting a secondary citation as if you had read the original
Common knowledge needs no citation, but what counts as common knowledge varies by field. When in doubt, cite. Similarity scores from checkers such as Turnitin are evidence, not a verdict: properly quoted text can score high and still be fine.
Side-by-side comparison
A work with three authors, 2021, quoted from page 45:
| Style | Parenthetical | Narrative | Three or more authors |
|---|---|---|---|
| APA 7 | (Kim et al., 2021, p. 45) | Kim et al. (2021) | et al. from the first citation |
| MLA 9 | (Kim et al. 45) | Kim and others | first author + et al. |
| Chicago 18 author-date | (Kim et al. 2021, 45) | Kim et al. (2021, 45) | first author + et al. |
| Chicago 18 notes | superscript + footnote | — | first author + et al. in notes |
| IEEE | [1, p. 45] | Kim et al. [1] | et al. for three or more names |
| Vancouver | (1) or ¹ | Kim et al. (1) | journal rules |
See et al. and author-count rules for the full comparison.
Checklist before you submit
- Every in-text citation matches a reference entry, and vice versa
- Every direct quotation has quotation marks (or block format) and a locator
- Author names and et al. use are consistent throughout
- Numeric citations follow order of first appearance, and repeated sources keep their number
- Secondary sources are marked as such
- Grouped citations follow the style's ordering rule
Build the reference list with the reference generator, and check the style guides for APA, MLA, Chicago, IEEE and Vancouver. Your university or journal's rules always take precedence.