When it comes to clinical trials, it can be difficult to track down related content. Not all journals publish the trial ID in the body of the article; therefore, although a results article may cite a published protocol, there is nothing to connect that article to subsequent publications. And nothing to link from the protocol to the results article.
It was in pursuit of this ambition that, in partnership with Crossref, BioMed Central called a cross-publisher meeting to discuss how to build on the well-established digital-object identifier (DOI) and the more recent CrossMark tool to achieve the threaded publication concept. Look for an update on this topic from Crossref and EM customer BioMed Central in early 2016!