<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31449690</termId><termName>rigid airships</termName><termType>PT</termType><termNote><![CDATA[ Airships that are held aloft by an envelope of gas that is supported by an internal framework rather than the pressure of the gas itself. ]]></termNote><termCreatedDate>2026-03-30 21:01:05</termCreatedDate><relation><relationType>UF</relationType><termId>31449691</termId><termName>rigid airship</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31426114</termId><termName>airships</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31449684</termId><termName>zeppelins</termName><termType>PT</termType></relation></term>  </Zthes>