Fetching Facebook URL for article:publisher

Hello,

First of all, great plugin. Very easy to install and get it up and running! Thank you so much for creating this.

I need a help in fetching the Facebook URL of respective author in individual blog pages to place in header:

<?php if (is_single()) { ?>
<meta property="article:publisher" content="<strong>FACEBOOK AUTHOR URL GOES HERE</strong>" />
<?php } ?>

Can you please help with the query?

Thanks in advance,
Jaseem