I'm almost certain one of the students who responds to professor Sheikh's questions is Isabella Weber. If you can confirm, I'd appreciate it. Her book on China's economy was fantastic!
Note: for those interested, the book professor Shaikh refers to around 29:00 on the history of currencies is called "A Survey of Primitive Monies" by Alison Quiggin. Although the book is not available on Amazon, the Amazon page for this book on 10/12/19 is: www.amazon.com/dp/0389040495/?coliid=I21194ESWKURKX&colid=3AACZVMJT49BF&psc=0&ref_=lv_ov_lig_dp_it