APA (7th ed.) Citation

Lewis, C. S., Lewis, W. H., & Hooper, W. (2017). Letters of C. S. Lewis (First edition.). HarperOne.

Chicago Style (17th ed.) Citation

Lewis, C. S., W. H. Lewis, and Walter Hooper. Letters of C. S. Lewis. First edition. San Francisco: HarperOne, 2017.

MLA (9th ed.) Citation

Lewis, C. S., et al. Letters of C. S. Lewis. First edition. HarperOne, 2017.