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mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">[materials by chemical form]</topic></authority><related type="narrower"><topic>compounds</topic></related><related type="narrower"><topic>elements</topic></related><related type="narrower"><topic>isotopes</topic></related><related type="narrower"><topic>chemicals</topic></related><related type="narrower"><topic>allotropes</topic></related><related type="broader"><topic>materials by form</topic></related></mads>