APA (7th ed.) Citation

Tolkien, J. R. R., Carpenter, H., & Tolkien, C. (2000). The letters of J.R.R. Tolkien: A selection (1st Houghton Mifflin pbk. ed.). Houghton Mifflin Co..

Chicago Style (17th ed.) Citation

Tolkien, J. R. R., Humphrey Carpenter, and Christopher Tolkien. The Letters of J.R.R. Tolkien: A Selection. 1st Houghton Mifflin pbk. ed. Boston: Houghton Mifflin Co., 2000.

MLA (8th ed.) Citation

Tolkien, J. R. R., et al. The Letters of J.R.R. Tolkien: A Selection. 1st Houghton Mifflin pbk. ed. Houghton Mifflin Co., 2000.