Finds a $page object in the collection by UID or relative URI
<?php echo $page->children()->find('subpage-a')->title() ?>
<ul>
<?php foreach($page->children()->find('subpage-a', 'subpage-c', 'subpage-i') as $subpage): ?>
<li>
<a href="<?php echo $subpage->url() ?>">
<?php echo html($subpage->title()) ?>
</a>
</li>
<?php endforeach ?>
</ul>