The Valkyrie : first day of the trilogy : The ring of the Niblung
MLA
Wagner, Richard. The Valkyrie: First Day of the Trilogy : The Ring of the Niblung. London: Schott & Co., [1900?]
APA, 7th edition
Wagner, R. ([1900?]). The Valkyrie: first day of the trilogy : The ring of the Niblung. London: Schott & Co
Chicago, 17th edition
Wagner, Richard. The Valkyrie: first day of the trilogy : The ring of the Niblung. London: Schott & Co., [1900?]