def METHOD_NAME(self, document_url, user_reference: str) -> str:
    """
    Get the public URL for VitalSource book viewer from our internal URL.
    That URL can be used to load VitalSource content in an iframe like we
    do with other types of content.
    :param document_url: `vitalsource://` type URL identifying the document
    :param user_reference: The user reference (you can use
        `get_user_reference()` to help you with this)
    """
    return self._sso_client.METHOD_NAME(
        user_reference, self.get_book_reader_url(document_url)
    )