@Override
  public RncFile getReferencedFile() {
    final String href = getFileReference();
    if (href != null) {
      final PsiFile file = XmlUtil.findRelativeFile(href, getContainingFile());
      if (file instanceof RncFile) {
        return (RncFile)file;
      }
    }
    return null;
  }
@Override
  public RncFile getReferencedFile()