Article Xu, Fengxian; He, Nu (2011)
A New Explanation on the Origination of the Idea of 1 cun for 1000 li for the Variation Rate of the Sun's Shadow. Ziran Kexueshi Yanjiu (Studies in the History of Natural Sciences) (pp. 151-169). (/isis/citation/CBB001210025/) unapi

Article He, Nu (2009)
On the Gnomon Shadow Template Function of the Lacquer Stick from the Royal Tomb IIM22 at the Taosi Walled-town of the Middle Period. Ziran Kexueshi Yanjiu (Studies in the History of Natural Sciences) (p. 251). (/isis/citation/CBB000933763/) unapi