//prep.ai.mit.edu/pub/gnu/">ftp://prep.ai.mit.edu/pub/gnu/</a>

   [<a name="ref-5" id="ref-5">5</a>] Schwartz, E. S., and Kallick, B. "Generating a canonical prefix
       encoding." Comm. ACM, 7,3 (Mar. 1964), pp. 166-169.

   [<a name="ref-6" id="ref-6">6</a>] Hirschberg and Lelewer, "Efficient decoding of prefix codes,"
       Comm. ACM, 33,4, April 1990, pp. 449-459.

<span class="h2"><a class="selflink" name="section-6" href="#section-6">6</a>. Security Considerations</span>

   Any data compression m