function num_titles()
{
require_once ROOT_DIR . '/sys/LocalEnrichment/UserListEntry.php';
//Join with grouped work to make sure we only load valid entries
$listEntry = new UserListEntry();
$listEntry->listId = $this->id;
require_once ROOT_DIR . '/sys/Grouping/GroupedWork.php';
$groupedWork = new GroupedWork();
$listEntry->joinAdd($groupedWork);
$listEntry->find();
return $listEntry->N;
}
