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IOP Science

Referencing for journal articles

It is vitally important that you fully acknowledge all relevant work. You should also consult the IOP ethical policy for journals for general guidance on compiling your reference list. You can find information on how to structure and format your references in the style guide for journal articles. Please note it is not necessary to format your references in the ways shown in the guidelines, however we find some authors like to have a style to work to. We will ensure your references adhere to house style during the production process, whatever format you submit them in.

A reference should give your reader enough information to locate the article concerned, and you should take particular care to ensure that the information is correct so that links to referenced articles can be made successfully.

Please also note the following:

  • Material that is really a footnote to the text should not be included in the reference list.
  • Copies of cited publications not yet available publicly should be submitted for the benefit of the reviewers.
  • Unpublished results and lectures should be cited for exceptional reasons only.
  • Please reference and link to the original Version of Record (where it was first published) rather than to other versions of an article and/or a link to a repository or third party database.
  • We discourage the referencing of online material hosted at web addresses that have no guarantee of perpetuity. Permanent or persistent web links should be used, as these are intended to remain unchanged for many years into the future, yielding hyperlinks that are less susceptible to ‘link rot’. Examples of acceptable links include: Digital Object Identifier (DOI), PubMed identifier (PMID), PubMed Central reference number (PMCID), SAO/NASA Astrophysics Data System (ADS) Bibliographic Code, and arXiv e-print number. If you have any questions regarding what constitutes an acceptable web link then please email the journal.
  • Before submitting your article, please ensure you have conducted a literature search to check for any relevant references you may have missed.

Be sure to check the ‘About the journal’ page for the journal your submitting to see if you need to list page numbers, article titles or a particular reference style in your submission.

Reference labelling systems

There are two main systems for labelling references.

In the Vancouver numerical system, references are numbered sequentially through the text. The numbers should be given in square brackets, e.g. [1], [4-7] etc., and one number can be used to refer to several instances of the same reference. The reference list at the end of the article then lists the references in numerical order, not alphabetically.

Alternatively, in the Harvard alphabetical system, the name of the author appears in the text together with the year of publication, e.g. (Smith 2001) or Smith (2001) (as appropriate). Where there are only two authors, both names should be given in the text, e.g. (Smith and Jones 2001) or Smith and Jones (2001). However, if there are more than two authors only the first name should appear followed by et al: (Smith et al 2001) or Smith et al (2001). If you refer to different works by one author or group of authors in the same year they should be differentiated by including a, b, etc, after the date (e.g. 2001a). If you refer to different pages of the same article, the page number may be given in the text, e.g. Smith (2001, p 39). The reference list at the end of your article using this system should be in alphabetical order.

Please use a single referencing system consistently throughout your article. You may use either of these two systems for your references (unless you are submitting to Fluid Dynamics Research, Physics in Medicine and Biology or Physiological Measurement, which require all references to be written using the Harvard alphabetical style, or Nuclear Fusion, which requires all references to be written using the Vancouver numerical system).