Hi,
For those interested in Rowehl there is another book in German callled: "Die fliegenden Augen des Oberst Rowehl".
See:
http://www.amazon.de/fliegenden-Auge.../dp/3981364937
(No mention of 3.(F)/Aufklärungsgruppe 121 as far as I can see).
PS. Still loking for Siegfried Knemeyer information who was, amongst a lot of other roles, a member of Kommando Rowehl.