sitolost/content/xtemplates/includes/show_source.html

{% if SHOW_SOURCE_IN_SECTION %}
    {% if article and article.show_source_url %}
    <section class="well" id="show-source">
        <h4>This Page</h4>
        <ul>
            <a href="{{ SITEURL }}/{{ article.show_source_url }}">Show source</a>
        </ul>
    </section>
    {% endif %}
{% endif %}