Gotterdämmerung
Die Walkure: Libretto
Das Rheingold: Libretto
Die Walküre
The Valkyrie (Die Walkure): English National Opera Guide 21 (English National Opera Guides)
Siegfried in Full Score (Dover Music Scores)
Das Rheingold
Das Rheingold / The Rhinegold: English National Opera Guide 35
Der Ring Des Nibelungen
I Saw the World End: A Study of Wagner's Ring (Clarendon Paperbacks)