APA

Napier Mary, . (1990). The powers of darkness. London: Bodley Head.

Chicago

Napier Mary, . 1990. The powers of darkness. London: Bodley Head.

Harvard

Napier Mary, . (1990). The powers of darkness. London: Bodley Head.

MLA

Napier Mary, . The powers of darkness. London: Bodley Head. 1990.