Thomson Reuters vs. George Mason University (or EndNote vs. Zotero): the Business End of Citation Management Software

Academic software can be big business, and these days there is increasing tension between its different sources – free, open source software and commercially provided software. In the case of citation management software, that tension just grew dramatically.

To defend its market for the popular (and profitable) EndNote software to manage bibliographic citations, global publishing giant Thomson Reuters – a $30 billion company – brought a $10 million lawsuit last month against George Mason University and the Commonwealth of Virginia. The complaint claims that rival open source Zotero software (created at GMU) had ‘reverse engineered’ EndNote to provide a new feature supporting proprietary EndNote citation formats in Zotero. They also claimed trademark infringement for using the EndNote name in documentation about the new feature.

Zotero is a free, open source software add-on to the popular Firefox web browser that rivals EndNote in features and is rapidly gaining popularity among scholars. It was created by faculty at the Center for History and New Media at George Mason University, home of several innovative open source projects aimed at historians and other scholars as they begin to exploit new opportunities provided by the web. Zotero’s initial development was supported by non-profit foundations and government agencies, including the Mellon Foundation and the US Institute for Museum and Library Services. In just a few short years Zotero has become a serious rival to commercial citation management tools, matching them feature for feature, in part by building a global community of open source software developers who know what researchers need from these tools and can act quickly to improve the product.

The lawsuit focuses on an alleged violation of George Mason University’s site license for EndNote, known as an end user license agreement or EULA, that explicitly forbids reverse engineering the software. The claim is that Zotero project staff, while employed by George Mason University, reverse engineered EndNote to develop support for its proprietary citation formats – a major selling point for EndNote and one of its strongest features. Specifically, the complaint states that the Center for History and New Media released “a new beta version of Zotero to the general public” on July 8, and adds, “A significant and highly touted feature of the new beta version of Zotero, however, is its ability to convert – in direct violation of the License Agreement – Thomson’s 3,500 plus proprietary .ens style files within the EndNote Software into free, open source, easily distributable Zotero .csl files.” Legal analysis of the case points out that Thomson Reuters chose not to claim direct copyright or patent violation against Zotero, but that part of the complaint involves ‘destroying Thomson’s customer base’ and that it also enjoined Zotero, effectively trying to shut the project down completely. The version of Zotero in question is still a beta release and has not been made available as a production release.

Fortunately, in addition to George Mason University’s active defense of the lawsuit, the Software Freedom Law Center is representing pro bono the Zotero developers and stands ready to defend them if Thomson Reuters brings, as it has threatened to do, further litigation against Zotero or its developers.

An interesting twist to the case is that Thomson had previously encouraged EndNote users (primarily scholars) to create their own citation format style sheets for use in the software, and to share them with each other via donation back to Thomson or by posting on public web sites. But now Thomson is enforcing sole ownership of those style sheets regardless of who created them or where they’re located. In other words, unbeknownst to them EndNote users have been creating and sharing proprietary EndNote style sheets for years, but only at Thomson Reuters’ discretion (Thomson’s website changed after the lawsuit was filed to make this policy of exclusivity explicit).

The MIT community uses a variety of bibliographic citation management tools including EndNote, Zotero, RefWorks, as well as other more DIY approaches. All three products are useful to scholars, with pros and cons for different features, and all three are improving – in part because of their rivalry. Competition between commercial and open source software ultimately benefits scholars with better choices. The MIT Libraries support these tools and offer training to the community (, as well as developing and testing new citation services such as Citeline ( that help scholars publish their bibliographies and reading lists on the web.

Clearly Thomson Reuters believes there is more at stake than a simple site license agreement, and is trying to stop a free, open source project that they fear could end a profitable line of business. As an advocate for the best available software for the MIT community, I can only hope that George Mason University prevails in court and continues to provide Zotero – a valuable project trying to make our work a little easier.

The full text of the complaint is available online at and the official statement from George Mason University is found at

– MacKenzie Smith, Associate Director for Technology, MIT Libraries