APA (7th ed.) Citation

Tolkien, J. R. R., Carpenter, H., & Tolkien, C. (1995). The letters of J.R.R. Tolkien : a selection / edited by Humphrey Carpenter, with the assistance of Christopher Tolkien: A selection. HarperCollins.

Chicago Style (17th ed.) Citation

Tolkien, J. R. R., Humphrey Carpenter, and Christopher Tolkien. The Letters of J.R.R. Tolkien : A Selection / Edited by Humphrey Carpenter, with the Assistance of Christopher Tolkien: A Selection. London: HarperCollins, 1995.

MLA (9th ed.) Citation

Tolkien, J. R. R., et al. The Letters of J.R.R. Tolkien : A Selection / Edited by Humphrey Carpenter, with the Assistance of Christopher Tolkien: A Selection. HarperCollins, 1995.

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