EMI Classics 5 19479 2, 14-CD Der Ring des Nibelungen box (Haitink / Symphonieorchester des Bayerischen Rundfunks); booklet p.16 credits panel, in the incoming folder as booklet.pdf: "Recorded: II & III.1988 (Die Walkuere), XI.1988 (Das Rheingold), XI.1990 (Siegfried), XI.1991 (Goetterdaemmerung), Herkulessaal der Residenz, Munich". Recording was stamped 1988 for all four operas of the cycle; each was in fact recorded in a different year.