try {
if (identifiers == null || identifiers.size()==0)
return null;
// Identifiers
IdentifierBag ibag = objectFactory.createIdentifierBag();
Iterator iditer = identifiers.iterator();
while (iditer.hasNext()) {
ExternalIdentifier extid = (ExternalIdentifier) iditer.next();
if (extid != null ) {
KeyedReference keyr = objectFactory.createKeyedReference();
ibag.getKeyedReference().add(keyr);
InternationalStringImpl iname = (InternationalStringImpl) ((RegistryObject) extid).getName();
String value = extid.getValue();
ClassificationScheme scheme = extid.getIdentificationScheme();