TCG Letter #577 / Carpenter Letter #202

Carpenter #201: Letter from J.R.R. Tolkien to Rayner Unwin • 7 September 1957 (#576)

Carpenter #200a: Letter from J.R.R. Tolkien to Rayner Unwin • 4 September 1957 (#1460)

Carpenter #207: Letter from J.R.R. Tolkien to Rayner Unwin • 8 April 1958 (#581)

Letter from J.R.R. Tolkien to Forrest J. Ackerman • ?11 April–c. 21 April and c. 28 April–5 May 1958 (#915)

Carpenter #210: Letter from J.R.R. Tolkien to Forrest J. Ackerman • 9 June 1958 (#584)

Carpenter #204a: Letter from J.R.R. Tolkien to Rayner Unwin • 13 December 1957 (#1461)

The Letters of J.R.R. Tolkien (1981), p. 261

Cartas de J.R.R. Tolkien, p. 387

The Letters of J. R. R. Tolkien: Revised and Expanded ed. (HarperCollins, UK), p. 377

“Being a cult figure in one’s lifetime is not at all pleasant”: Tolkien’s relationship with his fans, Letter mentioned at 2 minute 10 seconds

The J.R.R. Tolkien Companion and Guide - Chronology (2017), pp. 539-40

The J.R.R. Tolkien Companion and Guide - Reader's Guide Part 1 (2017), p. 19

See also the J.R.R. Tolkien Companion and Guide: Reader's Guide, Part 1, Film adaptations for more information on the Ackerman / Zimmerman project.

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