<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31345842</termId><termName>aplanats</termName><termType>PT</termType><termNote><![CDATA[ Symmetrical lens design created in 1866 by Steinheil, which formed the basis for most general-purpose lenses until the early 20th century. ]]></termNote><termCreatedDate>2026-03-30 20:33:17</termCreatedDate><relation><relationType>UF</relationType><termId>31345843</termId><termName>aplanat</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31345844</termId><termName>aplanatic lens</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31321570</termId><termName>photographic lenses</termName><termType>PT</termType></relation></term>  </Zthes>