include an article at the end of the invoice

I have an article called "Rental Agreement" its article id is 72.

How can I include the rental agreement at the end of the invoice.

What to write at the end of the order/invoice.php file?

When I add the article at the end:

This worked perfectly.
I added

{code}
<?php
$article =& JTable::getInstance("content");
$article->load(87);
echo $article->get("introtext");
?>
{/code}

to the bottom of the invoice, and now the "Terms and Conditions" are included in the invoice.
the Terms and Conditions are located in an article, so the client can easily amended them and update them.