APA
Harper M., . (1970). Spiritual warfare. London: Hodder & Stoughton.
Chicago
Harper Michael, . 1970. Spiritual warfare. London: Hodder & Stoughton.
Harvard
Harper M., . (1970). Spiritual warfare. London: Hodder & Stoughton.
MLA
Harper Michael, . Spiritual warfare. London: Hodder & Stoughton. 1970.