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<h2 id="references">References</h2> <ol> <li id="fn:1"><p>Telcordia, SR-2275 Issue 4: Telcordia Notes on the Network (October 2000) <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>AT&T, Notes on Distance Dialing (1968) <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Bell Telephone Magazine, 41(2) p.63 (1968) <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Telcordia, SR-2275 Issue 4: Telcordia Notes on the Network (October 2000) <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> </ol>