Plugin or shortcode for ISBN number?

I’ve had some help from a developer, and would like to share the solution:

function get_google_tag( $isbn_metadata ) {
return (
    /* '<span class="post-meta-key">Preview: </span>' . */
    '<script type="text/javascript" src="http://books.google.com/books/previewlib.js"></script>' .
    '<script type="text/javascript">' .
    'GBS_insertPreviewButtonPopup(\'ISBN:' . $isbn_metadata . '\');' .
    '</script>'
);
}