odes by letter
      or name or some other label.  Thus a <b>node label</b> array can
      be an auxilliary item of data.
    </p>

    <p>
      One format for storing graph information included the ability to
      store a numeric label, the node coordinates, and the neighbors
      of a node.  This is called the <b>grf format</b>.  There are a few
      utilities for displaying an image of a graph that has been
      represented in this format.
    </p>

    <h3 align = "center">
      Licensing:
    </