Source in the content end

Resolved:

<?php if(is_syndicated()): ?>
    <a target="_blank" href="<?php the_syndication_permalink(); ?>" title="<?php the_syndication_source(); ?>"><strong>Source:</strong> <?php the_syndication_source(); ?></a>
<?php endif; ?>

Source: https://feedwordpress.radgeek.com/wiki/templates/

=)