<?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://AATesaurus.cultura.gencat.cat/aat/getty_en">petroleum</topic></authority><related type="broader"><topic>petroleum and petroleum by product</topic></related> <note xml:lang="en"><![CDATA[ Complex mixture of hydrocarbons that occurs naturally beneath the earth's surface, viscous yellow to black in color. Petroleum is refined (i.e.,separated by distillation) into useable fractions. ]]></note></mads>