APA (7th ed.) Citation

Tolkien, J. R. R., & Tolkien, C. (2010). The legend of Sigurd and Gudrún. HarperCollins.

Chicago Style (17th ed.) Citation

Tolkien, J. R. R., and Christopher Tolkien. The Legend of Sigurd and Gudrún. London: HarperCollins, 2010.

MLA (9th ed.) Citation

Tolkien, J. R. R., and Christopher Tolkien. The Legend of Sigurd and Gudrún. HarperCollins, 2010.

Warning: These citations may not always be 100% accurate.