<http://schema.org/description>
"Digital music sellers, including Apple, Amazon, HMV and Napster, have agreed to start displaying the official Parental Advisory warning label on tracks and albums on their respective ..."^^<http://www.w3.org/2001/XMLSchema#string>
<http://thenextweb.com/apple/2011/12/20/apple-agrees-to-display-parental-advisory-warnings-on-itunes-music/>