Wikipedia:Digital Object Identifier
A Digital Object Identifier (DOI) is a unique identifier to a published work, similar in concept to an ISBN. Wikipedia supports the use of DOI to link to published content. Where a journal source has a DOI, it is good practice to use it, in the same way as it is good practice to use ISBN references for book sources.
There are several ways to cite a reference via DOI. In general, you should avoid entering explicit URLs to the doi.org website. By using one of the following methods, the actual links are centrally managed and can be adjusted if the external website alters the way the URLs must be formatted.
This method no longer works; do not use it. It used to automatically look up and fill out many details of the bibliography entry and format it as a proper citation rather than just a bare link to the article itself.
Note that these Wikipedia guidelines do not conform to revised DOI display guidelines issued by CrossRef, which recommend displaying DOIs in URL format, for example, 
This approach avoids a number of common issues with citations in Wikipedia: