public static function getLibrary()
    {
        if (!self::$library) {
            $app = Application::getFacadeApplication();
            $config = $app->make('config');
            $adapter = $config->get('concrete.cache.page.adapter');
            $class = overrideable_core_class(
                'Core\\Cache\\Page\\' . camelcase($adapter) . 'PageCache',
                DIRNAME_CLASSES . '/Cache/Page/' . camelcase($adapter) . 'PageCache.php'
            );
            self::$library = $app->build($class);
        }

        return self::$library;
    }