For a detailed examination of Wagner's sources for the Ring and his treatment of them, see, among other works, Deryck Cooke's unfinished study of the Ring, I Saw the World End, and Ernest Newman's Wagner Nights.
En detaljeret studie af Wagners kilder og hans behandling af dem findes i Deryck Cookes ufærdige værk, I Saw the World End, og i Ernest Newmans Wagner Nights.