Citation FAQ
Quick, accurate answers to the citation questions students actually ask — with links to the full guide or tool when you need more depth.
Citation basics
- What is a citation?
- A citation is a formal acknowledgment of a source you used, given in a standardized format. It has two connected parts: a brief marker in your text — like (Smith, 2020) or a footnote number — at the point where you use the source, and a full entry in your reference list with everything a reader needs to find the source: author, title, publication, date. Citing tells readers which ideas are borrowed, lets them verify your claims, and protects you from plagiarism.
- What's the difference between a citation, a reference, and a bibliography?
- In everyday use they overlap, but strictly: a citation is the in-text marker; a reference is the full entry it points to; and the reference list contains only sources you actually cited. A bibliographycan be broader — everything you consulted, cited or not. APA uses “References”, MLA uses “Works Cited”, and Chicago’s notes system typically pairs footnotes with a “Bibliography”. See How to Write a Bibliography.
- What's the difference between APA, MLA, and Chicago style?
- APA (7th ed.) is an author–date style used in psychology, education, and the sciences — in-text citations look like (Smith, 2020). MLA (9th ed.) is used in literature and the humanities — citations pair the author with a page number, like (Smith 23). Chicago offers two systems: notes-bibliography (footnotes; common in history) and author-date (similar to APA). The biggest practical differences are the in-text format, how author names are written, and title capitalization. Full comparison: APA vs MLA and APA vs Chicago.
- Which citation style should I use?
- First, check your assignment brief or the journal’s author guidelines — a required style always wins. If nothing is specified, follow your field’s convention: APA for psychology, education, nursing, and social sciences; MLA for literature and languages; Chicago for history; IEEE for engineering; Vancouver or AMA for medicine. When you’re free to choose, pick one style and apply it consistently. Our citation style quiz and style-choosing guide can narrow it down.
Citation mechanics
- What is a DOI and where do I find it?
- A DOI (Digital Object Identifier) is a permanent ID for a scholarly work, like 10.1000/xyz123 — unlike URLs, it never breaks. You’ll find it on the article’s first page, near the abstract on the journal’s website, or in the database record. Modern APA prefers citing it as a link: https://doi.org/10.1000/xyz123. If you have the DOI, the DOI to APA converter builds the whole reference from it. More in How to Find a DOI.
- How do I cite a source with no author?
- Move the title into the author’s position. In APA, start the reference with the title and use a shortened title in the in-text citation: (“Study Finds,” 2023). In MLA, do the same with the title in quotation marks or italics as appropriate. Before assuming there’s no author, check for an organizational author — a company, agency, or organization counts and is cited by name. Step-by-step: How to Cite: No Author.
- How do I cite a source with no date?
- Use the no-date abbreviation in place of the year: (Smith, n.d.) in APA, and simply omit the date element in MLA (adding an access date for online sources is encouraged). Check thoroughly first — copyright dates, “last updated” notes, and page footers often carry a usable date. Details: How to Cite: No Date.
- What does "et al." mean and when do I use it?
- Et al. is Latin for “and others” — it shortens long author lists. In APA 7, use it from the very first citation whenever a work has three or more authors: (Rivera et al., 2021). In MLA, use it in both the in-text citation and the works-cited entry for three or more authors. The period goes after “al.”, never after “et”. Our et al. calculator applies the rules for you.
- What is a hanging indent and how do I make one?
- A hanging indent formats a reference entry so its first line sits flush left and every following line is indented half an inch — the standard layout for APA, MLA, and Chicago reference lists. In Word: select the list and press Ctrl+T (Cmd+T on Mac). In Google Docs: Format → Align & indent → Indentation options → Special indent → Hanging. Never fake it with spaces — it breaks when text reflows. The Hanging Indent Formatter walks through every word processor.
- How do I cite the same source multiple times?
- Cite it at every point of use, but the reference list carries only one entry per source. In APA, repeat (Smith, 2020) as needed — with page numbers for direct quotes. In MLA, once the source is clear from context you may give just the page number. Chicago notes use a shortened form after the first full footnote. Full walkthrough: Citing the Same Source Multiple Times.
- What is an annotated bibliography?
- An annotated bibliography is a reference list where each citation is followed by a short paragraph (typically 100–200 words) that summarizes the source and evaluates its credibility and relevance to your project. The citations follow your normal style; the annotation sits beneath each entry, indented. Build one with the Annotated Bibliography Maker or read the full guide.
Citing digital sources
- How do I cite ChatGPT or other AI tools?
- APA 7 treats AI output as software, with the company as author: OpenAI. (2025). ChatGPT (Mar 2025 version) [Large language model]. MLA treats the AI as the “author” of the generated text and recommends describing the prompt. Two cautions: check whether your instructor allows AI use at all, and remember AI output isn’t retrievable by readers, so many instructors want the transcript in an appendix. Generators and examples: ChatGPT Citation Generator · How to Cite AI.
- How do I cite a quote from a website with no page numbers?
- Use an alternative locator. APA accepts a paragraph number — (Smith, 2023, para. 4) — or a section heading plus paragraph count. MLA simply omits the locator when none exists: (Smith). Don’t invent page numbers from your printout or PDF viewer; those aren’t stable. If the quote is hard to locate, name the section in your sentence to help readers find it.
- Can I cite Wikipedia?
- You can cite it formally (as an encyclopedia entry with the article’s permanent revision link), but most instructors don’t accept it as a scholarly source because anyone can edit it. The better move: use Wikipedia to orient yourself, then follow its footnotes to the underlying published sources and cite those. More in Wikipedia for Research.
Academic integrity
- What counts as plagiarism?
- Plagiarism is presenting someone else’s words, ideas, structure, or data as your own — whether copied verbatim, lightly reworded, translated, or generated by AI and unacknowledged. It includes self-plagiarism (reusing your own earlier work without disclosure) and mosaic plagiarism (stitching phrases from sources with small changes). The fix is always the same: quote or paraphrase properly and cite at the point of use. See How to Avoid Plagiarism.
- Do I need to cite paraphrased information?
- Yes. Paraphrasing changes the wording, not the ownership of the idea — every paraphrase needs a citation, just without quotation marks. The only exception is common knowledge: facts an educated reader would know or could find undisputed in many general sources. When unsure, cite it — over-citing is a style issue, under-citing is plagiarism. Our Paraphrase Checker helps verify your rewording is genuinely yours; see also Paraphrasing vs Quoting.
- What is a secondary ("as cited in") citation?
- It’s citing a source you haven’t read directly, but found quoted inside something you did read. APA format: (Freud, 1915, as cited in Smith, 2020) — only Smith goes in your reference list. Use it sparingly: the expectation is that you track down and read the original whenever it’s reasonably available, because the quoting author may have taken it out of context.
Still stuck?
Browse the full guide library, check the style cheat sheets, or just generate the citation and let the formatter apply the rules for you.