code: @Override
  	public List<String> getLinkedWorkbooks() {
  		List<String> result = new ArrayList<>();
  		if (this.currentWorkbook instanceof HSSFWorkbook) {
  			result = getLinkedWorkbooksHSSF();
      
  		} else if (this.currentWorkbook instanceof XSSFWorkbook) {
  			// use its API
  			for (ExternalLinksTable element: ((XSSFWorkbook)this.currentWorkbook).getExternalLinksTable()) {
  				result.add(element.getLinkedFileName());
  			}
  		} else {
  			LOG.warn("Cannot determine linked workbooks");
  		}
  		return result;
  	}
docs: Provides a list of filenames that contain workbooks that are linked with the current one. Officially supported only for new Excel format. For the old Excel format this is experimental
  
  @return list of filenames (without path) belonging to linked workbooks