Porter, Andrew, «Lovers with extra trimmings», The Times (London) August 21, 1998: «Only in recent years have directors taken it upon themselves to rewrite Wagner's stage actions, to intervene, to move from simplification to new invention. Jean-Pierre Ponnelle's idea at Bayreuth, in 1981, was that Isolde should not appear in Act Three but be an off-stage voice sounding in Tristan's mind»