Art Botterell; alert.identifier and alert.references: I'd like to propose for future versions of CAP the TC consider the specification of a Universally Unique Identifier (UUID) as the value of alert.identifier and of entries in alert.references. While this would make the identifiers longer, it would reduce the risk of non-unique identifiers and simplify the construction of references. UUIDs are spec'd in ITU X.667 and IETF RFC 4122.