a href = "gr_grf.m">gr_grf.m</a>,
          writes a GRF file of a graph.
        </li>
        <li>
          <a href = "gr_incidence_matrix.m">gr_incidence_matrix.m</a>,
          computes the incidence matrix.
        </li>
        <li>
          <a href = "i4mat_print.m">i4mat_print.m</a>,
          prints an I4MAT;
        </li>
        <li>
          <a href = "i4mat_print_some.m">i4mat_print_some.m</a>,
          prints some of an I4MAT;
        </li>
        <li>
          <a href = "i4mat_transpose