Vocalists are capable of producing a variety of extended technique sounds. These alternative singing techniques have been used extensively in the 20th century, especially in art song and opera. Particularly famous examples of extended vocal technique can be found in the music of Luciano Berio, John Cage, George Crumb, Peter Maxwell Davies, Hans Werner Henze, György Ligeti, Demetrio Stratos, Meredith Monk, Giacinto Scelsi, Arnold Schoenberg, Salvatore Sciarrino, Karlheinz Stockhausen, Avi Kaplan, and Trevor Wishart.