1<p class="Pp"><span class="Rs"><span class="RsA">David Waitzman</span>, 2 <cite class="RsB">A Standard for the Transmission of IP Datagrams on Avian 3 Carriers</cite>, 4 <a class="RsR" href="https://www.rfc-editor.org/rfc/rfc1149.html">RFC 5 1149</a>, <span class="RsD">April 1990</span>.</span></p> 6