The Penguin history of the twentieth century : the history of the world, 1901 to the present

MLA

Roberts, J. M. The Penguin History of the Twentieth Century : the History of the World, 1901 to the Present. London: Penguin, 2000.

APA

Roberts, J. M. (2000). The Penguin history of the twentieth century : the history of the world, 1901 to the present. London: Penguin.

Chicago

Roberts, J. M. The Penguin History of the Twentieth Century: The History of the World, 1901 to the Present. London: Penguin, 2000.