public function getOperationByRel($rel, $single = true)
    {
        $operations = isset($this->object['operations']) ? $this->object['operations'] : [];
        $operation  = array_filter($operations, function ($value, $key) use ($rel) {
            return (is_array($value) && $value['rel'] === $rel);
        }, ARRAY_FILTER_USE_BOTH);

        if (count($operation) > 0) {
            $operation = array_shift($operation);

            return $single ? $operation['href'] : $operation;
        }

        return false;
    }