The Wikipedia Cite-o-Meter provides a conservative estimate of the number of times journal articles from a particular publisher are cited in the 100 largest Wikipedias. Using the Wikipedia API, Cite-o-Meter searches for occurrences of a DOI prefix in the main namespace of these Wikipedias (example).
A Digital Object Identifier (DOI) is a string used to uniquely identify objects such as electronic documents. DOIs are the de facto standard for uniquely identifying scholarly publications such as journal articles. A DOI (such as 10.1371/journal.pone.0011273) is composed of two parts — a prefix (10.1371) and a suffix (journal.pone.0011273). An article is uniquely identified by a DOI, which can be looked up using the DOI resolver. The example article is located at http://dx.doi.org/10.1371/journal.pone.0011273.
The DOI prefix is specific to a DOI registrant - the organization that handles the assignments of DOI suffixes for items published under that prefix. Most scholarly publishers operate as a single registrant, yet due to mergers and acquisitions, some publishers run several DOI prefixes. The DOI prefix 10.1371 is handled by the Public Library of Science (PLoS), and it is the only DOI prefix handled by PLoS. As a result, Cite-o-Meter statistics for this prefix provide a lower bound for citations to PLoS articles in Wikipedia.
Cite-o-Meter data is available in the form of graphs, tabular data and machine-readable JSON and is released under a CC0 license.