Sources and location of pharmaceutical internal company documents.

1Documents are grouped in rows where the articles are linked by a common set of authors working with the same set of documents.2Vedula and colleagues (Vedula et al 2009) included in their analysis internal company documents from a 2004 litigation that were also used by other authors in two articles (Steinman et al 2007 and Landefeld and Steinman 2009), and in addition analyzed documents from a 2008 litigation that were not used in other articles.