The Ring of the Niblung / Richard Wagner. Transl. by Margaret Armour. With illustr. by Arthur Rackham. London [u.a.] : Ballantyne & Co., 19XX. Badische Landesbibliothek Karlsruhe,
https://nbn-resolving.org/urn:nbn:de:bsz:31-143487 / CC-BY-SA-Lizenz (4.0)