ar-production-PN_CHARS">PN_CHARS</a><code>)</code> <code>?</code> </td>
    </tr>
    <tr id="tg-grammar-production-LANGTAG">
      <td>[144s]</td>
      <td><code>LANGTAG</code></td>
      <td>::=</td>
      <td>"<code class="grammar-literal">@</code>" <code>[</code> <code class="grammar-literal">a-zA-Z</code><code>]</code> <code>+</code>  <code>(</code> "<code class="grammar-literal">-</code>" <code>[</code> <code class="grammar-literal">a-zA-Z0-9</code><code>]</code> <code>+</code> <code>)</code> <code>*