{# single reference marker for histogram viz; expects a reference dict as returned by summary_value #}
{% url 'books:reference' derridawork_slug=ref.derridawork__slug page=ref.derridawork_page pageloc=ref.derridawork_pageloc as ref_url%}
{# NOTE: omitting id attribute (formerly id="tt{{ ref.id }}" because ids are not distinct for multi-author works and id is not used #}