the sample program.
        </li>
        <li>
          <a href = "scpack_prb_output.txt">scpack_prb_output.txt</a>,
          the output from a run of the sample program.
        </li>
      </ul>
    </p>

    <p>
      <ul>
        <li>
          <a href = "scpack_prb.xy">scpack_prb.xy</a>,
          an XY file containing node coordinates.
        </li>
        <li>
          <a href = "scpack_prb.xyl">scpack_prb.xyl</a>,
          an XYL file listing the indices of nodes that form lines.
        </li>
