e list of factors.
        </li>
      </ul>
    </p>

    <p>
      The resulting product rule files:
      <ul>
        <li>
          <a href = "ccgl_d2_o3x2_x.txt">
          ccgl_d2_o3x2_x.txt</a>,
          the abscissas of a 2D Clenshaw Curtis product rule of order 6.
        </li>
        <li>
          <a href = "ccgl_d2_o3x2_w.txt">
          ccgl_d2_o3x2_w.txt</a>,
          the weights of a 2D Clenshaw Curtis product rule of order 6.
        </li>
        <li>
          <a href = "ccgl_d2_o3x2_r