Online and internet sources are cited the same way as print, you just add three extra elements: a media-type label like [Online], an access date in the form [Accessed 24 June 2026], and an availability statement that gives the address of the source, such as Available at: followed by the URL. For a web page, an online article, an e-book, a video, or a social-media post, you keep the usual order of author, title, and further details, then add these online elements at the end. Output from an AI tool such as ChatGPT is not addressed directly by most citation styles, but you can cite it using the guidance of your institution and library. This article covers only what is specific to electronic sources. For the general approach, see the article how to cite ISO 690.
What makes a source "electronic" and why it matters
An electronic (online) source is any document you access through the internet or another digital medium: a web page, a downloadable PDF, an e-book, the online version of a scholarly study, a video, a social-media post, or a record in a database. It differs from a print source in two ways that directly affect the reference.
First, online content can change or disappear at any time. That is why referencing styles such as Harvard, APA, and MLA ask you to record when you actually viewed the source, namely the access date. Second, the reader needs to know exactly where the source is, so you add an availability statement (the URL or DOI). Without these two elements, a reference to an electronic source is incomplete.
Which style you follow depends on your field and your institution. Harvard and APA dominate the social sciences and sciences, while MLA is common in the humanities. If your department prescribes a particular style, follow its handbook. The official style guide always takes precedence over general advice.
The elements you add to every online source
When you cite an electronic source, you supplement the usual details with a few specific elements. Their order and form are settled within each style.
Media-type label: [Online]
Right after the title of the document, some styles ask you to add a square-bracketed label noting that this is an online source, for example [Online]. This signals to the reader that it is not a print version and that the source should be looked for on the internet. APA does not use this label, while many Harvard variants do, so check your handbook.
Access date
The access date tells the reader when you viewed the source and took details from it. For online sources it is often required, because content can change. In Harvard it usually appears as (Accessed: 24 June 2026); in MLA as Accessed 24 June 2026 at the end of the entry. APA generally asks for a retrieval date only when the content is likely to change over time, such as a wiki or a live data page.
Availability statement: Available at: / URL or DOI
At the end of the reference you state where the source is, using a phrase such as Available at: followed by the address, or simply the URL or DOI. Modern style guides do not put the address in angle brackets, and you do not place a full stop right after a URL where it might be copied by mistake. Wherever a DOI exists, prefer it to a plain URL.
Sample formats for different source types
The patterns below show the order and structure of the elements, not real sources. Square brackets with capital letters mark the places you replace with your own details. Small things (commas, italics, the exact wording) vary by style, so treat these as templates and confirm against your handbook.
Web page
For a standalone web page you give the author or organisation, the title of the page, an online label where the style uses one, the year or date, the access date, and the URL:
AUTHOR (or ORGANISATION). Year. Title of page [Online]. Available at: https://www.example.com/page (Accessed: 24 June 2026)
Online article or PDF in a scholarly journal
An online journal article combines details of the article with details of the journal. If the article has a DOI, you give it instead of, or alongside, the URL:
SURNAME, Initial. Year. Title of article. Journal Name [Online], volume(issue), pages. Available at: https://doi.org/10.xxxx/xxxxx (Accessed: 24 June 2026)
If it is a standalone PDF with no journal (for example a methodological handbook), cite it as an online document: author, year, title [Online], publisher, access date, and availability.
E-book
An e-book is cited much like a print book, but you add the format and the online elements:
SURNAME, Initial. Year. Title of book [Online]. Edition. Place: Publisher. Available at: https://www.example.com/book (Accessed: 24 June 2026)
If you read the e-book in a specific format or reader, you can note the format (for example [Kindle] or [EPUB]) according to your style guide.
Video (for example YouTube)
For a video, the author is the creator or channel that published the content. You give the title of the video, the format, the channel or platform, the date of publication, the access date, and the URL:
AUTHOR or CHANNEL. Year. Title of video [Online video]. Platform. Available at: https://www.youtube.com/watch?v=xxxx (Accessed: 24 June 2026)
Social-media post
For a social-media post you give the author's name, optionally the username in brackets, the wording or a description of the post, the platform, the exact date (and time if needed), and the URL:
AUTHOR (@username). Year. Text or description of post [Online]. Platform, date and time. Available at: https://www.example.com/post (Accessed: 24 June 2026)
Online newspaper and news portals
An online news article combines the author, the headline, the title of the publication, and the online elements. If no author is named, you start with the title of the article:
SURNAME, Initial. Year. Headline of article. Newspaper Name [Online]. Date of publication. Available at: https://www.example.com/article (Accessed: 24 June 2026)
Databases and repositories
For sources from scholarly databases and repositories you give, in addition to the usual details, the name of the database and the availability. If a DOI or a permanent link is available, prefer it to a long address with session parameters:
SURNAME, Initial. Year. Title of document [Online]. Database Name. Available at: https://doi.org/10.xxxx/xxxxx (Accessed: 24 June 2026)
DOI versus URL: which to prefer
A DOI (Digital Object Identifier) is a permanent identifier that leads to the document even when its web address changes. A URL is an ordinary internet address that may move or stop working over time. If a source has a DOI, give it preferentially, usually as a link in the form https://doi.org/ followed by the identifier.
The practical rule is simple. Does the source have a DOI? Use the DOI. It does not? Use the most permanent URL you can, ideally a permalink or stable link rather than a temporary address from a search. Long addresses with session parameters (the parts after a question mark that expire when you close the browser) are left out.
What to do when the author or date is missing
Web sources often lack an author or a date of publication. Citation styles anticipate this and offer clear solutions.
- No author. Begin the reference with the title of the document. Do not invent an author or write "anonymous". If an organisation is responsible for the content (an agency, a body, a school), name it as the author.
- No date of publication. Instead of the year, write (no date) in Harvard or (n.d.) in APA. You still add the access date, which you always know, because it is the day you viewed the source.
- No title. Social-media posts often have no formal title. In that case give a short description of the content or the first few words of the post.
- No page number. For an online source without pagination you do not cite a page. If the content is long, you can point to a chapter, a section, a paragraph number, or a timestamp (for a video).
The shared rule is this: never invent details that are not in the source. It is better to use the prescribed substitute (title instead of author, n.d. instead of the year) than a false detail.
How (and whether) to cite output from AI tools
Most citation styles do not directly address citing output from generative AI tools such as ChatGPT, though APA and MLA have published specific recommendations. Before you cite AI, check two things: whether your institution allows AI in your work at all, and how it wants you to document its use. The rules of your department or supervisor always take precedence.
When you need to mention an AI tool
If you used AI as a source of information or to generate part of the text, you must disclose and document it. If you used it only to fix spelling or rephrase your own sentences, it is usually enough to mention this in a note on methodology. The line between a tool and a source is set by your institution's policy. Remember too that AI output can be detected, more on that in the article how AI-generated text is detected.
Sample structure of an AI-tool reference
The recommendations agree that you should cite the tool itself, not "a conversation" as an anonymous source. The reference should contain these elements:
CREATOR. Year. Name of tool. Type of source, version [Large language model]. Available at: https://www.example.com (Accessed: 24 June 2026)
In practice this means: the creator (for example the company that developed the tool), the name of the tool, a note that it is a generative AI tool, its version, the date, and the availability. Because AI output is not publicly traceable and cannot be verified by others, many institutions recommend including the conversation itself (your prompt and the response) in an appendix, with date and time. That way the examiners can check exactly what the tool produced.
Why caution is warranted
An AI tool is not a trustworthy primary source. It can "make up" facts and even nonexistent citations, so every detail from it must be verified in a real source, and you cite that original document. Use AI at most as an aid to orient yourself in a topic, not as a source on which you rest the claims in your work. In academia the rule is that you are responsible for the content and its verification, not the tool.
The most common mistakes when citing online sources
- A missing access date. The most common mistake with electronic sources. For an online source it is often required, because the content can change.
- A full stop after the URL. Style guides avoid placing a full stop right after the final address, so that it does not become part of the copied link.
- A temporary address instead of a permanent one. Copying a long address from a search or with session parameters. Use a permanent link or a DOI.
- Citing a whole domain. The reference should lead to a specific document or subpage, not just to the home page of a site.
- AI as an anonymous source. A claim such as "according to the internet" or "according to AI" without identifying the tool and without verification in the original source.
If you are unsure about your citations, it can help to look at our overview of services, where we can check the formatting and the reference list against your chosen style.
Frequently asked questions
What is the difference between the publication date and the access date?
The publication date is the day the source was published or last updated. The access date is the day you viewed the source and took details from it. For online sources both are given where available. The access date is often required, because online content can change.
Do I need an access date for a printed book?
No. The access date is specific to electronic and online sources, where the content can change over time. For a printed book or journal the publication date is enough, because a print document no longer changes.
How do I cite a source that has since disappeared from the internet?
If you viewed the source while writing and cited it properly with an access date, the reference remains valid even if the page later goes offline. The access date documents exactly when the source was available. Where possible, archive a copy (for example a saved page or a screenshot).
Can I cite Wikipedia or a blog in my thesis?
Technically yes, formally you cite them as a web page. The real question is whether it is a suitable source. Wikipedia and blogs are not primary scholarly sources. In academic work use them at most as a starting point and base your claims on scholarly studies, books, and official documents.
How do I cite an online source that has no author?
Begin the reference with the title of the document. If an organisation is responsible for the content (an agency, a school, a body), name it as the author. Never invent an author or write "anonymous".
Is it allowed to cite ChatGPT as a source in a bachelor's or master's thesis?
It depends on the rules of your institution. Most citation styles do not address AI directly, but APA, MLA, and many departments publish their own recommendations. If AI is allowed, you cite the tool itself (creator, name, version, date, availability) and ideally attach the conversation in an appendix. Always check the policy of your department or supervisor.
I need help with my citations. Can you check them?
Yes. If you are unsure about formatting or your reference list, our writers can help you align your citations with your chosen style. You can look at our services or simply place a no-obligation order, and we will advise on what your work needs.