APA (7th ed.) Citation

Pliny, t. Y. (1963). The letters of the younger Pliny. Penguin Books.

Chicago Style (17th ed.) Citation

Pliny, the Younger. The Letters of the Younger Pliny. Baltimore, Md: Penguin Books, 1963.

MLA (9th ed.) Citation

Pliny, the Younger. The Letters of the Younger Pliny. Penguin Books, 1963.