1. A method of media asset management comprising the steps of: encapsulating into each of an aggregation of assets an external specific identifier associated with each asset for a corresponding application, wherein the asset comprises references to a media essence with corresponding production rights, wherein the aggregation of assets also has a unique identifier, wherein the productions rights comprise metadata, and the external specific identifier is associated with specific media production and distribution rights, and wherein the external specific identifier is stored separately from a database storing the essence; and querying the aggregation of assets with a given application using said specific identifier for that application to identify at least one asset associated with said identifier.