When mentioned in the text, only surnames of authors are used. For a 2-author reference, list both surnames; for references with more than 2 authors or authors and a group, include the first author’s surname followed by “et al”.

Superscript numbers

The numbers in text are in superscript¹ and occur at the end of the clause in which you used the information. They occur outside “quotation marks,”² commas,³ (parentheses)⁴ and full stops.⁵ However, they occur inside semicolons⁶; and colons⁷:

Do not leave a space between the last letter or punctuation mark and the number.

Re-use numbers for the same citation

Citations should be numbered sequentially – that is, the first source you cite is 1, the second source is 2 and so on.

However, once you have given a source a number, it will keep that number throughout your paper. So, if you use your first source again, no matter how often you use it, it is still 1.

Citing more than one work at a time

Use commas to show that more than one work is being cited, and use hyphens for several works that would be numbered sequentially:

These side effects can have implications for the patient's mental health, as numerous studies have shown.^1,3,6-9

Relationship between in-text citations and reference list

Your reference list follows the order of the numbers used in the text. The first source you cite in the text is 1 and the reader will look for number 1 in the reference list to find the full citation; the fifth source you use is 5 and the full citation is listed at number 5 in the reference list (and so on).

Notes:

Avoid placing a superscript reference citation immediately after a number or an abbreviated unit of measure to avoid any confusion between the superscript reference citation and an exponent.

Avoid: The 2 largest studies to date included 26² and 18³ patients.

Better: The 2 largest studies to date included 26 patients² and 18 patients.³

In the medical sciences, you should only use a direct quote if the exact wording is important.  You should be paraphrasing the information as much as possible. When paraphrasing, it is not standard practice to use page numbers, but they can be used if you feel it is necessary for clarification.

However, if you do need to refer to the exact wording used by the authors, you must put the quote in "quotation marks" and use a page number next to the in-text citation.

You put the page number in brackets directly after the reference number, with no space: 1(p6). This all goes in superscript.

Example

Rey's support of the Mad Dog theory is equivocal, and he states "I’m not defending Mad-doggery because I believe it."^3(p125)