1. Huang Di Nei Jing (The Yellow Emperor's Inner Classic), 480-220 B.C.
2. Institute of the History of Natural Sciences, Chinese Academy of Sciences. Ancient China's Technology and Science. Beijing: Foreign Languages Press, 1983.
3. Needham J. Science and Civihsation in China: Volume II. Richmond, UK: Kingprint, 1972.
4. Needham J. Clerks and Craftsmen in China and the West. Cambridge, UK: Cambridge University Press, 1970.
5. Unschuld P, ed. Nan-Ching: The Classic of Difficult Issues. Berkeley: University of California Press, 1986.