Original: Zezong, Xi, "The Discovery of Jupiter's Satellite Made by Gan De 2000 years Before Galileo," Chinese Physics 2 (3) (1982): 664–67.
Simplified: Xi Zezong, "The Discovery of Jupiter's Satellite Made by Gan De 2000 years Before Galileo," Chinese Physics 2 (3) (1982): 664-67.