APA (7th ed.) Citation

Gwynn, A. (1968). The twelfth-century reform. Gill.

Chicago Style (17th ed.) Citation

Gwynn, Aubrey. The Twelfth-century Reform. Dublin [u.a.]: Gill, 1968.

MLA (9th ed.) Citation

Gwynn, Aubrey. The Twelfth-century Reform. Gill, 1968.