@abc.abstractmethod<EOL><INDENT>def references(self, uri, request):<DEDENT>
This method checks if a certain uri is being referenced by any other
resource within this application.

:param string uri: URI of the resource we need to check for
:param request: :class:`pyramid.request.Request` with useful configuration information and connections
                of the application (registry, route_url, session) to determine the references
:rtype: :class:`pyramid_urireferencer.models.ApplicationResponse`