<http://schema.org/headline>
"String Quartet No. 4 Sz91: II. Prestissimo, con Sordino by Keller Quartet"^^<http://www.w3.org/2001/XMLSchema#string>
<https://www.songpop2.com/content/song/Keller-Quartett_String-Quartet-No-4-Sz91-II-Prestissimo-con-/QsN8a>