Direct link to ETF research PDF linked from the thread:
https://www.sec.gov/comments/sr-nysearca-2019-01/srnysearca2...
Interesting things to see in the hundreds of pages:
page 24: What Do Real Exchanges Look Like?
page 43: Trade Size Histograms For Suspect Exchanges
page 57: Applying All Three Analyses: BitForex
page 111: We Have Reached The Point Of Diminishing Returns For Improvements In Efficiency