for(int c = lCol; c <= rCol; ++c) {
sheet.setColumnHidden(c, hidden);
}
final Book book = (Book) sheet.getWorkbook();
final RefSheet refSheet = BookHelper.getRefSheet(book, sheet);
final Ref ref = new AreaRefImpl(0, lCol, book.getSpreadsheetVersion().getLastRowIndex(), rCol, refSheet);
final Set<Ref> all = new HashSet<Ref>();
all.add(ref);
return all;
}