APA (7th ed.) Citation

Childs & Keegan. (2001). Warfare in the seventeenth century. Cassell.

Chicago Style (17th ed.) Citation

Childs and Keegan. Warfare in the Seventeenth Century. London: Cassell, 2001.

MLA (8th ed.) Citation

Childs and Keegan. Warfare in the Seventeenth Century. Cassell, 2001.