The Routledge companion to the crusades.

MLA

Lock, Peter. The Routledge Companion to the Crusades. London: Routledge, 2006.

APA

Lock, P. (2006). The Routledge companion to the crusades. London: Routledge.

Chicago

Lock, Peter The Routledge Companion to the Crusades. London: Routledge, 2006.