Cita APA (7a ed.)

Ball, R. (1908). Natural sources of power (1a ed.). Constable.

Cita Chicago Style (17a ed.)

Ball, Robert. Natural Sources of Power. 1a ed. Londres: Constable, 1908.

Cita MLA (9a ed.)

Ball, Robert. Natural Sources of Power. 1a ed. Constable, 1908.