黒門の戦い
↑ Shippey, Tom (2005) [1982]. The Road to Middle-Earth (Third ed.). Grafton (HarperCollins). pp. 226–227. ISBN 978-0261102750
1 2 Kocher, Paul (1974) [1972]. Master of Middle-earth: The Achievement of J.R.R. Tolkien. Penguin Books. pp. 140–141. ISBN 978-0-14-003877-4
↑ Timmons, Daniel (2006). Croft, Janet Brennan. ed. Tolkien and Shakespeare: essays on shared themes and language. McFarland & Co. p. 87. ISBN 0-7864-2827-9. https://books.google.com/books?id=-WGaDtnHUOYC&pg=PA87
↑ Shippey, Tom (1983). The Road to Middle-earth. Houghton-Mifflin. p. 116. ISBN 978-0-395-33973-2
↑ Bassham, Gregory; Bronson, Eric (2012). The Hobbit and Philosophy: For When You've Lost Your Dwarves, Your Wizard, and Your Way.