Find articles that cite a given article, or that a given article cites

Articles that cite a given article

This example E-Link call returns a list of articles in PMC that cite the given article in PubMed:

This will return the numerical portion of the PMCIDs. So, for example, 3930942 corresponds to article PMC3930942.

You can retrieve citing articles for a set (two or more) of given articles, in one call:

This does the same thing, but returns PMIDs, rather than PMCIDs:

Another variation: using "pmc_pmc_citedby" lets you specify the cited article by PMCID:

Articles that a given article cites

This is the reverse of the above use-case. Given a PMCID, you can find all of the articles that it cites with an E-Link call such as the following:

The following does the same thing, but the "given article" is identified by PMID, rather than PMCID:

The "pmc_pmc_cites" link returns only those cited articles that are in PMC: