TCG Letter #423 / Carpenter Letter #329

The Letters of J.R.R. Tolkien (1981), p. 414

The J.R.R. Tolkien Companion and Guide - Chronology (2017), p. 794

The Letters of J. R. R. Tolkien: Revised and Expanded ed. (HarperCollins, UK), pp. 580-81

J.R.R. Tolkien A Descriptive Bibliography, Di1, p. 350

Silke Anzinger, "Von Troja nach Gondor.Tolkiens „The Lord of the Rings“ als Epos in vergilischer Tradition," in Vestigia Vergiliana: Vergil-Rezeption in der Neuzeit edited by Thorsten Burkard , Markus Schauer and Claudia Wiener. (2010) pp. 363-401. p. 373 note 36

Tolkien's Faith: A Spiritual Biography, p. 4

Cartas de J.R.R. Tolkien, pp. 589-90