1. Baoji N.(2011).Pig farms can receive up to 800 000 yuan in subsidy in Baoji. Baoji News March 22 [Online]. Available at:http://www.cschenxin.com/zhu/news/910339.shtml[Accessed 12 December 2020].
2. Taphonomy at a Distance: Zhoukoudian, "The Cave Home of Beijing Man"? [and Comments and Reply]
3. Central Document Research Institute(1983).Party central committee notice on releasing the “several questions of current rural policies” [Online]. Available at:http://www.reformdata.org/1983/0102/7467.shtml[Accessed 8 March 2021].