<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31458814</termId><termName>arch keystones</termName><termType>PT</termType><termNote><![CDATA[ Wedge-shaped stones at the apex of masonry arches. ]]></termNote><termCreatedDate>2026-03-30 21:03:30</termCreatedDate><relation><relationType>UF</relationType><termId>31458815</termId><termName>arch keystone</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31458816</termId><termName>keystones, arch</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31440313</termId><termName>keystones</termName><termType>PT</termType></relation></term>  </Zthes>