def serialize_oaipmh(self, pid, record):
        """Serialize a single record for OAI-PMH."""
        root = etree.Element(
            'oai_datacite',
            nsmap={
                None: 'http://schema.datacite.org/oai/oai-1.0/',
                'xsi': 'http://www.w3.org/2001/XMLSchema-instance',
                'xml': 'xml',
            },
            attrib={
                '{http://www.w3.org/2001/XMLSchema-instance}schemaLocation':
                'http://schema.datacite.org/oai/oai-1.0/ oai_datacite.xsd',
            }
        )

        root.append(E.isReferenceQuality(self.is_reference_quality))
        root.append(E.schemaVersion(self.serializer.version))
        root.append(E.datacentreSymbol(self.datacentre))
        root.append(E.payload(
            self.serializer.serialize_oaipmh(pid, record)
        ))

        return root