Top tips

Be consistent
Don't mix and match styles. All citations should follow the same format.

You don’t need to memorise the styles
All details are on the library website, so you can easily check.

Don’t lose marks by missing a citation! If you do, you could be committing plagiarism.

To write a citation, you first need to decide on your referencing style. At Imperial, most departments use either the Harvard or Vancouver styles, but you should check before you start writing. If you are asked to use another style ask your librarian for advice.


The Harvard style uses an author-date system, so to cite within the text you need to know the author and the date of publication. You would usually put them both in brackets. In your work, it would look like this:

A recent study investigated the effectiveness of using Google Scholar to find medical research (Henderson, 2005).

Where a source has three authors or fewer, include all names in the citation. For four or more authors use the first named author, followed by 'et al'. You can find more examples here in our Harvard citing guide


The Vancouver style uses numbers in the text. You can either put the numbers in brackets or use superscript numbers. For example:

Recent research (1) indicates that the number of duplicate papers being published is increasing.


Recent research1 indicates that the number of duplicate papers being published is increasing.

Each individual reference is assigned a number when it is first used. If you refer to it more than once, you use the same number again. You can find more examples in our Vancouver citing guide.