I think one guy already said it but this is an extra answer in case you may need, it actually has some bootstrap 3 style:
<!-- Previous and Next Post -->
<?php if(is_single()) : ?>
<!-- Para pantallas grandes -->
<div class="btn-group btn-group-justified hidden-sm hidden-xs" role="group" aria-label="..." id="nextpreviouslinks">
<div class="btn-group" role="group">
<button type="button" class="btn btn-default btn-sm"> Previous Post: <?php previous_post_link( '%link', '%title'); ?></button>
</div>
<div class="btn-group" role="group">
<button type="button" class="btn btn-default btn-sm"><a href="<?php bloginfo('url') ?>"><i class="fa fa-th" aria-hidden="true"></i></a></button>
</div>
<div class="btn-group" role="group">
<button type="button" class="btn btn-default btn-sm"> Next Post: <?php next_post_link( '%link', '%title' ); ?></button>
</div>
</div>
<?php endif; ?>
<!-- /Previous and Next Post -->