* @return the crop box
     */
    public Rectangle getCropBox(final int index) {
        PdfDictionary page = pageRefs.getPageNRelease(index);
        PdfArray cropBox = (PdfArray)getPdfObjectRelease(page.get(PdfName.CROPBOX));
        if (cropBox == null)
            return getPageSize(page);
        return getNormalizedRectangle(cropBox);
    }