1. A method of coding structured data made of items, at least part of the items being defined by structural information and content information, the structured data including information representing content values according to a plurality of versions for items having the same structural information, the method comprising: a step of determining, from the structured data, a structure that includes content items, a single content item defining the structural information for items having the same structural information, wherein the structure includes identifying information to identify the content items therein corresponding to items that have content information, and determining content values associated with the content items identified in said structure according to the plurality of versions; a step of associating, with each content item identified in said structure, a determined content value for each version of plurality of versions, to provide association information that lists the content values according to the plurality of versions for each content item identified in said structure; and a step of encoding the structured data by coding, in a single file: information representing the plurality of versions; the association information representing said association between each content item identified in said structure and its respective content values for the plurality of versions and listing the content values according to the plurality of versions for each content item identified in said structure, and said structure of the structured data, wherein at least one of the foregoing steps is performed by one or more processors.