@Override
  public PsiReference @NotNull [] getReferences() {
    final PsiElement dtdUrlElement = getDtdUrlElement();

    PsiReference uriRef = null;
    if (dtdUrlElement != null) {
      uriRef = createUrlReference(dtdUrlElement);
    }

    final PsiReference[] refs = ReferenceProvidersRegistry.getReferencesFromProviders(this);

    return uriRef == null ? refs : ArrayUtil.mergeArrays(new PsiReference[] {uriRef}, refs);
  }
@Override
  public PsiReference @NotNull [] getReferences()