Roberts, J. M. (1999). Twentieth century : the history of the world, 1901 to the present / J. M. Roberts: The history of the world, 1901 to the present. Allen Lane.
Chicago Style (17th ed.) CitationRoberts, J. M. Twentieth Century : The History of the World, 1901 to the Present / J. M. Roberts: The History of the World, 1901 to the Present. London: Allen Lane, 1999.
MLA (9th ed.) CitationRoberts, J. M. Twentieth Century : The History of the World, 1901 to the Present / J. M. Roberts: The History of the World, 1901 to the Present. Allen Lane, 1999.
Warning: These citations may not always be 100% accurate.