<?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://general-terms.thesaurus.ekt.gr/vocab">chemical formulae</topic></authority><related type="narrower"><topic>empirical formulae</topic></related><related type="narrower"><topic>molecular formulae</topic></related><related type="narrower"><topic>stereochemical formulae</topic></related><related type="narrower"><topic>structural formulae</topic></related></mads>