code: public MusicElement getElementByReference(MusicElementReference ref) {
  		if (voiceExists(ref.getVoice())) {
              for (Object o : getVoice(ref.getVoice())) {
                  MusicElement element = (MusicElement) o;
                  if (element.getReference().equals(ref))
                      return element;
              }
  		}
  		return null;
  	}
docs: Returns an element for the given reference, <TT>null</TT> if not found