Tignor, R. L., Adelman, J., Brown, P., Elman, B., Liu, X., Pittman, H., & Shaw, B. (2008). Worlds together, worlds apart: A history of the world from the beginnings of humankind to the present (Second edition.). W.W. Norton & Company.

Tignor, Robert L., Jeremy Adelman, Peter Brown, Benjamin Elman, Xinru Liu, Holly Pittman, and Brent Shaw. Worlds Together, Worlds Apart: A History of the World from the Beginnings of Humankind to the Present. Second edition. New York: W.W. Norton & Company, 2008.

Tignor, Robert L., et al. Worlds Together, Worlds Apart: A History of the World from the Beginnings of Humankind to the Present. Second edition. W.W. Norton & Company, 2008.