Digital Object Identifiers (DOIs) are special strings of alphanumeric characters that form a persistent link to individual publications. They are issued at the time of publication, much like an ISBN or a serial number. DOIs can be attached to a number of different publications, including journal articles, books and chapters, conference papers, and so on.
A number of referencing styles (including APA 6th, Chicago, and Vancouver) require that you include DOIs for publications where they have been assigned. This guarantees that others will be able to access your listed references, as DOIs offer persistence and permanence that standard URLs (links) do not.
To check if DOIs are used with your required referencing style, see our style guides indexed on the left.
Some DOIs are listed as the full link (shown above), others will be included as a part of the source information (along with the journal name, etc).
Sometimes DOIs will be on the cover sheet, other times they will be located towards the top or the bottom of the first page of the publication (as shown above).
Not all publications have a DOI, and not all databases list DOIs where available.
If you are unable to locate a DOI for your publication, you can check the free DOI lookup services at CrossRef which works for all DOIs (not just journal articles).
Metadata search is the easiest way to use CrossRef, and can be done by simply entering your title into the search box on the main page and clicking on the Search button (circled in red, below).
The results will then be displayed in a screen similar to the one below:
Note that using this search will also provide a number of results that are similar to the publication that you're searching for, so always check that you have the correct publication.
If you are still unable to find a DOI, end the reference as you would normally (according to your required referencing style) for a resource without a DOI.
If you have a DOI, you can go to http://dx.doi.org/ and type or paste it into the search box.
This will ‘resolve’ the DOI and take you to the publisher’s site or database where you may be able to download the full text, and/or export the citation into your citation management software.sp
Note that some DOIs may not ‘resolve’ due to problems with publisher databases, and/or the Library may not have subscription access directly via the publisher. Where this is the case, see our PDF guide to finding articles: