public function loadContentTypeGroupList(Request $request)
    {
        if ($request->query->has('identifier')) {
            $contentTypeGroup = $this->contentTypeService->loadContentTypeGroupByIdentifier(
                $request->query->get('identifier')
            );

            return new Values\TemporaryRedirect(
                $this->router->generate(
                    'ezpublish_rest_loadContentTypeGroup',
                    array(
                        'contentTypeGroupId' => $contentTypeGroup->id,
                    )
                )
            );
        }

        return new Values\ContentTypeGroupList(
            $this->contentTypeService->loadContentTypeGroups(Language::ALL)
        );
    }