Base URL valid for all of catalog items. Absolute item URL is made sipmly by concatenation base URL and relative item URL Root element. Date qualified element. Content shoud be formated conformly to WTN8601 scheme. Contains allways value WTN8601. Qualifier is required Qualifier is required. Can contain values: "created"; "expired"; "generated"; "modified"; "published"; "registered"; "removed"; "valid"; Simple type date and time Unique identifiers of the catalog item Item element URL of the catalog item Simple type URL