The Life Sciences Core XML Schema provides core data types used for interoperability. Global Life Sciences Identifier attribute Element can be used as a reference to an object named by the LSID A Life Sciences Identifier (LSID) is a URN that uniquely names an object. The syntax is urn:lsid:<authority>:<namespace>:<value>:<version> where authority is the name of the organization that has defined an entity, namespace is a namespace within the authority for the Id, value is an alpha-numeric sequence that uniquely identifies an object to its authority, and version is a version number for an Id. <authority> and <namespace> can have hierarchical path elements separated by "/".