A new(and long awaited) book:
"Special Forces Berlin: Clandestine Cold War Operations of the US Army's Elite, 1956–1990" by James Stejskal
https://smile.amazon.com/dp/B06WLLJPGB/
I haven't read it yet as I only just received the alert and downloaded it immediately.
Considering how little the world knows about DET-A and the resurgence of Cold War 2.0 in Eastern Europe that renews their relevancy, I'm just grateful to get a better open source understanding of their history.