Previous and next buttons outside the single post loop

<?php $posts = query_posts($query_string); if (have_posts()) : while (have_posts()) : the_post(); ?>
<div class="post-entries ym65">
    <div class="previous"><?php previous_post('%', '<span>&#9668;</span> Previous Article', 'Yes'); ?></div>
    <div class="next"><?php next_post('%', 'Next Article <span>&#9658</span>;', 'Yes'); ?></div>
</div>
<?php endwhile; endif; ?>