<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://roble.intecca.uned.es/tematres/lem/">Metales alcalinoterreos</topic></authority><related type="narrower"><topic>Bario</topic></related><related type="narrower"><topic>Berilio</topic></related><related type="narrower"><topic>Estroncio</topic></related><related type="narrower"><topic>Magnesio</topic></related><related type="narrower"><topic>Radio (Metal)</topic></related><related type="narrower"><topic>Calcio</topic></related><related type="broader"><topic>Metales ligeros</topic></related></mads>