h program for how they treat ambiguous symbols.</p>
      </div>

    </div>

    <h3 id="additional">Additional Information</h3>
    <div class="indent">

      <h4 id="allowed_chars">Allowed Symbol Characters</h4>
      <div class="indent">
        <p>Each <span class="pdat">symbol</span> is a single <b>letter</b>, <b>number</b> or
        one of the <b>four special characters</b> '.', '-', '*' or '?'. 
        Letters may be either
        uppercase or lowercase (see <a href="#one_case">Letter Case</a>
 