TCG Letter #413 / Carpenter Letter #318

The Letters of J. R. R. Tolkien: Revised and Expanded ed. (HarperCollins, UK), pp. 569-70, p. 635 (Carpenter notes)

The Letters of J.R.R. Tolkien (1981), pp. 405-06, p. 453 (Carpenter notes)

The J.R.R. Tolkien Companion and Guide - Chronology (2017), pp. 45 (see entry for End of Hilary Term or beginning of Trinity Term 1913), 47 (see entry for Trinity Term 1913), 789

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

Tolkien's The Lord of the Rings. Sources of Inspiration, p. 31, see note 54, p. 32, see note 55

Tolkien and the Great War, p. 30 (Switch in courses)

Cartas de J.R.R. Tolkien, pp. 579-80, p. 646 (notas de Carpenter)