Cita APA

Brown, G. G., & Brown, G. G. (1972). The twentieth century. London: Ernest Benn Limited.

Citación estilo Chicago

Brown, Gerald Griffiths, y Gerald Griffiths Brown. The Twentieth Century. London: Ernest Benn Limited, 1972.

Cita MLA

Brown, Gerald Griffiths, y Gerald Griffiths Brown. The Twentieth Century. London: Ernest Benn Limited, 1972.