How to Cite Sources Correctly
Citing sources does two jobs: it gives credit to the people whose work you used, and it lets readers verify and follow your evidence. Done right, it also protects you — uncited borrowing is plagiarism even when accidental.
Here's the whole system: when a citation is needed, the two parts every citation has, how styles differ, and the workflow that keeps it painless.
When you need a citation
What doesn't need citing: common knowledge (Paris is the capital of France), your own analysis and conclusions, and your own results in the paper that reports them.
- Direct quotes — any words that aren't yours, in quotation marks, cited with a page or locator.
- Paraphrases — someone else's idea in your words still needs the citation; rewording transfers nothing.
- Data, statistics, and findings — numbers always have a source.
- Images, charts, and tables you didn't create.
- Contested or surprising claims — anything a skeptical reader would ask "says who?" about.
Every citation has two parts
Part one — in the text: a short marker at the point of use. Author–date in APA and Harvard: (Rasch & Born, 2013); author–page in MLA: (Rasch and Born 685); a numbered bracket in IEEE: [1]; a footnote in Chicago.
Part two — the reference list: the full entry with everything needed to find the source. The two parts must match one-to-one — every marker points to an entry, every entry is pointed to. Example of a full entry:
Rasch, B., & Born, J. (2013). About sleep's role in memory. Physiological Reviews, 93(2), 681-766. https://doi.org/10.1152/physrev.00032.2012
Which style? Your field decides
APA — psychology, education, nursing, social sciences. MLA — English, literature, humanities. Chicago — history, art history, publishing. Harvard — common across UK and international universities. IEEE — engineering and computer science. Your syllabus or journal guidelines override everything; when free to choose, see How to Choose a Citation Style.
A workflow that doesn't hurt
- Cite as you research, not after. Reconstructing sources at 2 a.m. is how citations get faked or dropped.
- Capture the identifier — the URL, DOI, or ISBN is all you need; the generator rebuilds the rest.
- Save as you go — a free account keeps your citation history and projects so nothing is lost between sessions.
- Build the list automatically — the Bibliography Builder alphabetizes, formats, and exports to Word with correct indents.
- Read each citation once before submitting — generators inherit source metadata; thirty seconds of review catches the odd miscredited page.
The mistakes that cost marks
- Citing in the text but forgetting the reference entry (or vice versa).
- Citing the homepage instead of the specific page.
- Paraphrasing without citing — the most common accidental plagiarism.
- Mixing styles — an MLA entry on an APA references page.
- Citing an abstract or a secondary mention instead of the work itself.
Keep every citation you make.
A free account saves your citation history and organizes sources into projects with notes and tags.
Create a free account →Find the sources you should be citing.
Premium searches 250 million scholarly works by topic, recommends citations for your claims, and flags statements in your writing that need support.
Go Premium — $5/monthFrequently asked questions
- How many citations does a paper need?
- As many as it makes claims that aren't yours — there's no quota. A typical research paper cites every quoted or paraphrased source plus data sources; quality and relevance beat count.
- Can I cite Wikipedia?
- Usually not directly — most instructors disallow it as a source. Use it as a map: its references section points to citable primary sources.
- Do I need to cite something twice if I use it twice?
- In the text, yes — every borrowed passage gets its marker. The reference list carries one entry per source regardless of how often it's cited.
- What's the fastest way to cite everything correctly?
- Paste each source's URL, DOI, or ISBN into the generator as you research, add to bibliography, and export at the end. The formatting rules are applied for you.