Can't get tablesorter to work

Can't get tablesorter to work

I'm trying to use the jQuery tablesorter plugin to sort a table.

I have this in the head section of the page:

<script type="text/javascript" src="tablesorter/jquery.tablesorter.js"></script>
<script
              src=" https://code.jquery.com/jquery-3.1.1.slim.min.js"
              integrity="sha256-/SIrNqv8h6QGKDuNoLGA4iret+kyesCkHGzVUUV0shc="
              crossorigin="anonymous"></script>
<script>
    $(document).ready(function()
        {
            $("#Library").tablesorter();
        }
    );
    </script>

And this in the body:

<table class="WBATable tablesorter" id="Library" >  
      <thead>  
      <tr>
        <th>Title</th>
        <th>Author</th>
        <th>Publisher</th>
        <th>Publication Date</th>
        <th># Pages</th>
        <th>Subject</th>
      </tr>
      </thead>
      <tbody>
      <?php do { ?>
        <tr>
          <td><?php echo $row_rs_books['Title']; ?></td>
          <td><?php echo $row_rs_books['Author']; ?></td>
          <td><?php echo $row_rs_books['Publisher']; ?></td>
          <td class="center"><?php echo $row_rs_books['Publication_Date']; ?></td>
          <td><?php echo $row_rs_books['Pages']; ?></td>
          <td><?php echo $row_rs_books['Category']; ?></td>
        </tr>
        <?php } while ($row_rs_books = mysql_fetch_assoc($rs_books)); ?>
        </tbody>
     </table>
  
The page is online here. http://www.westsidebridgeacademy.com/WBA_LIbrary.php.

Can anyone point out what I'm doing wrong?