Coba jelasin Rujukan dari Zhang Heng dalam bahasa melayu dong

Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2: Mechanical Engineering. Taipei: Caves Books, Ltd.

Wright, David Curtis (2001) The History of China. Westport: Greenwood Press.

Huang, Ray (1997). China: A Macro History. New York: An East Gate Book, M. E. SHARPE Inc.