List Author Wordpress Functions

function contributors() {
global $wpdb;

$authors = $wpdb->get_results("SELECT ID, user_nicename from $wpdb->users WHERE display_name <> 'admin' ORDER BY display_name");

$authors_per_page = 10;
$page = isset( $_GET['cpage'] ) ? abs( (int) $_GET['cpage'] ) : 1;

echo paginate_links( array(
    'base' => add_query_arg( 'cpage', '%#%' ),
    'format' => '',
    'prev_text' => __('«'),
    'next_text' => __('»'),
    'total' => ceil($total / $authors_per_page),
    'current' => $page
));

foreach ($authors as $author ) {

echo "<li>";
echo "<a href=\"".get_bloginfo('url')."/author/";
the_author_meta('user_nicename', $author->ID);
echo "/\">";
echo get_avatar($author->ID);
echo "</a>";
echo '<div>';
echo "<a href=\"".get_bloginfo('url')."/author/";
the_author_meta('user_nicename', $author->ID);
echo "/\">";
the_author_meta('display_name', $author->ID);
echo "</a>";
echo "<br />";
echo "SitoWeb: <a href=\"";
the_author_meta('user_url', $author->ID);
echo "/\" target='_blank'>";
the_author_meta('user_url', $author->ID);
echo "</a>";
echo "<br />";
echo "Twitter: <a href=\"http://twitter.com/";
the_author_meta('twitter', $author->ID);
echo "\" target='_blank'>";
the_author_meta('twitter', $author->ID);
echo "</a>";
echo "<br />";
echo "<a href=\"".get_bloginfo('url')."/author/";
the_author_meta('user_nicename', $author->ID);
echo "/\">Visita il Profilo di ";
the_author_meta('display_name', $author->ID);
echo "</a>";
echo "</div>";
echo "</li>";
}
}