APA (7th ed.) Citation

Lewis, C. S., Calabria, G., & Moynihan, M. (1988). Letters: C.S. Lewis [and] Don Giovanni Calabria : a study in friendship. Colins.

Chicago Style (17th ed.) Citation

Lewis, C. S., Giovanni Calabria, and Martin Moynihan. Letters: C.S. Lewis [and] Don Giovanni Calabria : A Study in Friendship. London: Colins, 1988.

MLA (9th ed.) Citation

Lewis, C. S., et al. Letters: C.S. Lewis [and] Don Giovanni Calabria : A Study in Friendship. Colins, 1988.