JACOBSEN, Lyle E. Use of Knotted String Accounting Records in Old Hawaii and Ancient China. accountingin.com [online]. [cit. 2023-01-08]. Dostupné online. (anglicky)
bbc.co.uk
news.bbc.co.uk
RINCON, Paul. 'Earliest writing' found in China. BBC News [online]. 2003-04-17 [cit. 2023-01-08]. Dostupné online. (anglicky)
The Quipu, the Pre-Inca Data Structure [online]. gogeometry.com [cit. 2023-01-08]. Dostupné online. (anglicky)
google.cz
books.google.cz
[1] Wee Lee Woon, Chinese Writing: Its Origin and Evolution, „Since these signs on the Banpo pottery all occur singly, and are in any case limited in number, our picture of Chinese writing in this period is still hazy.“
Institute of Vertebrate Paleontology. Engraved stone artifact found at the Shuidonggou Paleolithic Site, Northwest China. phys.org [online]. 2012-12-24 [cit. 2023-01-08]. Dostupné online. (anglicky)
Oldest known alphabet unearthed in ancient Syrian city. phys.org [online]. Phys.org, 2024-11-20 [cit. 2024-11-21]. Dostupné online.