Linked Clinical Trials is a CrossRef initiative helping to connect the published literature to registered clinical trials associated with the research, - version 1.0 (initial release) September 24, 2015 Accommodates deposit of linked clincal trials metadata. The clinical-trial-number value will be a string that must match a specific pattern appropriate for a given clinical trial registry. The registry is identified in the required attribute 'registry' and must be the DOI of a recognized registry (see http://dx.doi.org/10.18810/registries) The clinical trial identifier related to the article. Used to identify the article publication date in relation to the issuance of the trial results