public function getPage($index)
{
$criteria = new Criteria();
$criteria->add(QubitInformationObject::PARENT_ID, $this->informationObject->id);
$criteria->addJoin(QubitInformationObject::ID, QubitDigitalObject::INFORMATION_OBJECT_ID);
$criteria->setLimit(1);
$criteria->setOffset($index);
return QubitDigitalObject::getOne($criteria);
}