code: public void assignModelReferences(XAttributable target,
  			List<String> modelReferences) {
  		StringBuilder sb = new StringBuilder();
  		for (String ref : modelReferences) {
  			sb.append(ref);
  			sb.append(" ");
  		}
  		if (sb.toString().trim().length() > 0) {
  			XAttributeLiteral attr = (XAttributeLiteral) ATTR_MODELREFERENCE
  					.clone();
  			attr.setValue(sb.toString().trim());
  			target.getAttributes().put(KEY_MODELREFERENCE, attr);
  		}
  	}
docs: Assigns to a log element (i.e., archive, log, trace, event, or attribute)
  a list of model references.
  
  @param target
  Any log element (i.e., archive, log, trace, event, or
  attribute) to be assigned references to.
  @param modelReferences
  The list of model references, as a list of strings, referred
  to by this element.