Source:http://linkedlifedata.com/resource/umls/id/C1563337
HL7V3.0: <p>The notion of a document comes particularly from the paper world, where it corresponds to the contents recorded on discrete pieces of paper. In the electronic world, a document is a kind of composition that bears resemblance to their paper world counter-parts. Documents typically are meant to be human-readable.</p><p>HL7's notion of document differs from that described in the W3C XML Recommendation, in which a document refers specifically to the contents that fall between the root element's start-tag and end-tag. Not all XML documents are HL7 documents.</p>