How to cite sources in slides: per slide, footer, references
Cite on the slide where the material appears, not only on a references slide at the end: a short line at the bottom (author, year, page or figure) for every claim, figure, table or quotation that is not yours, and a references slide listing the full entries once. In APA style the in-text form is (Author, Year, p. X); on a slide that line is the citation, and the references slide is the bibliography.
This guide covers where the citation goes, how short it can be, the forms for the four things you cite most (a claim, a figure, a table, a quotation), the references slide, and how a Markdown deck keeps the trail so the citation is never separated from the slide.
Why on the slide and not just at the end?
Because a student photographs the slide, not the deck. A figure with no source line is an uncredited figure wherever it ends up; a claim with no source is unanswerable when a student asks "where is this from?". The references slide is for the reader who wants the full entry; the per-slide line is for everyone in the room.
For teaching there is a second reason: the source line is the link between the slide and the reading, and a deck whose every slide names its reading is a deck a student can study from.
The per-slide line
One line at the bottom of the slide, smaller than the body text:
- A claim from a text:
Silberschatz et al., 2018, §5.3.2 - A figure:
Figure: Tanenbaum & Bos, 2015, fig. 2-9(oradapted from, if you redrew it) - A table or data:
Data: Dean & Barroso, 2013, table 1 - A quotation: the quotation in quotation marks on the slide, then
Brooks, 1975, p. 16
Author, year, and a location. The location is what makes the line useful: a page, a section, a figure number. Without it the line says "somewhere in this book".
In APA terms this is the in-text citation, with a locator; MLA and Chicago have their equivalents (author–page, note number). Use the style the department uses for essays; nobody expects a slide to carry more.
Figures need the line most
Figures travel. A redrawn figure still cites the original ("adapted from"); a screenshot of a figure cites it and, for anything you publish beyond the classroom, needs permission. Put the line directly under the figure rather than in the slide footer, so it stays with the image if the slide is rearranged.
The references slide
One slide at the end, or one per section in a long deck, with the full entries in the department's style, alphabetical. It can be small type; it is there to be photographed, not read from the back row. Every per-slide line must resolve to an entry here, and nothing here should lack a slide.
If the deck comes from a reading list, the references slide is that list, and it doubles as the "what to read" slide.
Keeping the trail in a Markdown deck
In a text deck the citation is part of the slide's text, so it cannot be lost:
---
# Convoy effect
Short processes wait behind one long one; throughput falls.
<small>Silberschatz et al., 2018, §5.3.1</small>
<!--
Source: os-book 5.3.1, figure 5.2. Ask: where would this show up in the lab data?
-->
The <small> line is the visible citation; the comment is the speaker note with the same source, for the question from the room. A theme can style a .source class instead of <small> and pin it to the bottom of every slide. A search for a source name then finds every slide that uses it, and a deck built from a reading list can be checked against it: every slide cites something on the list, and every list item is cited.
Citing with an assistant in the loop
If an assistant writes a slide, require the source and location on the slide as part of the request, then check the location against the reading. A slide that reads well but points nowhere is the failure mode. Lecture Studio writes decks from the readings attached to a course and cites them under each answer and on the slides; the sources are indexed so the assistant searches them rather than the open web. The app runs on macOS 15 or later and needs an Oberik project key; it is free during the beta.
FAQ
How do I cite a source on a PowerPoint or Google Slides slide?
A small line at the bottom of the slide with author, year and a page or figure number, plus a references slide at the end with the full entries.
Do I need a citation on every slide?
On every slide that contains someone else's claim, figure, table or words. A slide of your own explanation needs none.
How do I cite an image in a presentation?
Directly under the image: author or source, year, and "fig. N" or a URL, with "adapted from" if you redrew it. Add the full entry to the references slide.
Does a references slide replace in-slide citations?
No. The references slide gives the full entries; the per-slide line is what tells the audience where each thing came from.