Use secondary sources very sparingly, usually only when you cannot obtain the original work (e.g. it is out-of-print). Where possible, you should read the original work.
In your reference list, give the details of the secondary work. In the text, name the original work and give a citation for the secondary source. (Section 6.17).
Arrow found that the role of leaders in the social choice tradition derives from the well-known instability in social choice (as cited in Ahlquist & Levi, 2011).
Reference list for example above:
Ahlquist, J. S. & Levi, M. (2011). Leadership: What it means, what it does, and what we want to know about it. Annual Review of Political Science, 14, 1-24.
In-text: (Ahlquist & Levi, 2011)
Secondary in-text citation: (as cited in Ahlquist & Levi, 2011)
"Reference twins," or two (or more) references by the same author (or the same group of authors listed in the same order) published in the same year, are organised n the reference list alphabetically by the title of the article or chapter. Assign letter suffixes to the years to differentiate between or among the references. Read more here.
Koriat, A. (2008a). Easy comes, easy goes? The link between learning and remembering and its exploitation in metacognition. Memory & Cognition, 36, 416-428. https://doi.org/10.3758/MC.36.2.416
In-text: (Koriat, 2008a).
Koriat, A. (2008b). Subjective confidence in one’s answers: The consensuality principle. Journal of Experimental Psychology: Learning, Memory, and Cognition, 34, 945-959. https://doi.org/10.1037/0278-7393.34.4.945
In-text: (Koriat, 2008b).
If there is no author for a particular webpage or source, move the title to the first position. (However, before doing this, DOUBLE CHECK to make sure there really is no author. For more information, read this APA Style blog post.)
All 33 Chile miners freed in flawless rescue. (2010, October 13). Retrieved from http://www.msnbc.msn.com/id/39625809/ns/world_news-americas/
In-text: ("All 33 Chile Miners Freed," 2010).
The APA Style blog has some helpful articles on cultural variations in names and name order. Please refer to the following posts:
The APA Style team has written a blog post on Citing generative AI in APA Style in September 2025, pertaining to citing AI chats.
The APA Style team provided a template for reference and in-text citations for a specific AI chat, formatted as follows:
Reference citation
AI Company Name. (year, month day). Title of chat in italics and sentence case [Decription, such as Genrative AI chat]. Tool Name/Model.
URL of the chat
In-text citation
Parenthetical citation: (AI Company Name, year)
Narrative citation: AI Company Name (year)
Here are some specific examples:
Prompt used in an AI chat: “I’d like a list of grammar topics that a student should understand by the time they graduate from high school.”
Reference citations
Anthropic. (2025, May 20). Essential grammar topics for high school graduates [Generative AI chat]. Claude Sonnet 4. https://claude.ai/share/329173b2-ec93-4663-ac68-4f65ea4f166d
Google. (2025, May 22). High school grammar concepts overview [Generative AI chat]. Gemini 2.5 Flash. https://g.co/gemini/share/a1306ce12929
OpenAI. (2025, August 21). High school grammar concepts [Generative AI chat]. ChatGPT. https://chatgpt.com/share/68a77b60-0ee4-800c-9acc-cd3fd573c311
Perplexity AI. (2025, May 20). High school grammar topics [Generative AI chat]. Perplexity. https://www.perplexity.ai/search/a457cb8c-c663-4c9b-b34e-cb03d8108b35
In-text citations
Parenthetical citations: (Anthropic, 2025; Google, 2025; OpenAI, 2025; Perplexity AI, 2025)
Narrative citations: Anthropic (2025), Google (2025), OpenAI (2025), and Perplexity AI (2025)
The 4 key elements to note are:
Author: The company responsible for developing the AI tool; for example, OpenAI is the author of ChatGPT, and Google is the author of Gemini.
Date: The specific year, month, and day on which a chat occurred or concluded.
Title: The title of the chat (in italic sentence case) followed by a bracketed description to clarify for readers the nature of the source; for example, “[Generative AI chat].”
Source: Begins with the name of the AI tool, which can be general (e.g., ChatGPT or Gemini) or the name of the model (e.g., ChatGPT-5 or Gemini 2.5 Flash). The final piece of the source element is the URL of the chat.
In addition, it is also possible to cite an AI tool generally and NOT a specific chat. Here is the template for citing an AI tool generally:
Reference citation
AI Company Name. (year). Tool Name/Model in Italics and Title Case [Decription, such as Large language model].
URL of the tool
In-text citation
Parenthetical citation: (AI Company Name, year)
Narrative citation: AI Company Name (year)
Here are some specific examples:
Reference citations
Anthropic. (2025). Claude 4 Sonnet [Large language model]. https://claude.ai/new
Google. (2025). Gemini 2.5 Flash [Large language model]. https://gemini.google.com
OpenAI. (2025). ChatGPT [Large language model]. https://chatgpt.com/
Perplexity AI. (2025). Perplexity [Large language model]. https://www.perplexity.ai/
In-text citations
Parenthetical citations: (Anthropic, 2025; Google, 2025; OpenAI, 2025; Perplexity AI, 2025)
Narrative citations: Anthropic (2025), Google (2025), OpenAI (2025), and Perplexity AI (2025)
The 4 key elements to note are:
Author: The company responsible for developing the AI tool; for example, OpenAI is the author of ChatGPT, and Google is the author of Gemini.
Date: The year in which the AI tool was most recently updated. (If you are unsure of the date, ask the AI.)
Title: The name of the AI tool, which can be general (e.g., ChatGPT or Gemini) or the name of the model (e.g., ChatGPT-5 or Gemini 2.5 Flash). Then, include a description of the AI in brackets; for example, “[Large language model]” for chat tools.
Source: The URL of the AI tool.
Please read the APA Style Blog for more details.