APA (7th ed.) Citation

O'neill, R. (1992). The Middle Ages. Crescent Books.

Chicago Style (17th ed.) Citation

O'neill, Richard. The Middle Ages. London: Crescent Books, 1992.

MLA (9th ed.) Citation

O'neill, Richard. The Middle Ages. Crescent Books, 1992.

Warning: These citations may not always be 100% accurate.