itle.  Invoked with any other non-numeric
argument, (e.g. <kbd>OFF</kbd>, <kbd>NO</kbd>, <kbd>X</kbd>, etc.)
the macro disables underlining of the title.
</p>

<p>
In addition, you can use BIBLIOGRAPHY_STRING_UNDERSCORE to control
the weight of the underscore rule(s), the gap between the title and
the underscore, and, in the case of double-underscores, the distance
between the two rules.
</p>

<p>
Some examples:
<br/>
<span class="pre-in-pp">
  .BIBLIOGRAPHY_STRING_UNDERLINE 1
      - turn underlining on; s