Flat or Globe Earth?, page-592

I'm still waiting to here which book on Geometry he uses as a reference.
eg As yet I can't find his geometry based flat earth reasoning in this one or others.

https://www.amazon.com.au/Geometry-Comprehensive-Course-DAN-PEDOE/dp/0486658120/ref=asc_df_0486658120?mcid=87649c9dcca73382adca4c318701c91c&tag=googleshopdsk-22&linkCode=df0&hvadid=712376980013&hvpos=&hvnetw=g&hvrand=5316490965842912763&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9070819&hvtargid=pla-448533027742&psc=1&gad_source=1