APA Style

Guinness, O. (2003). The call : finding and fulfilling the central purpose of your life / Os Guinness. . Nashville, Tenn.: W. PUB. GROUP.

MLA Style

Guinness, Os.. "The call : finding and fulfilling the central purpose of your life / Os Guinness.". Nashville, Tenn.: W. PUB. GROUP, 2003. Text.