United States National Archives.
RG 457.2: Records of the National Security Agency/Central Security Service, 1917-1993.
US Army, Signals Intelligence Service.
Germany. Ref. No.: XXXXXXXXX
Copy No.: 221
the Office of the Fuhrer for the attention of SS Brigadefuhrer EICHMANN, BERLIN.
Subject: Status Report on EINSATZ ERFURT.
The doctor reports satisfactory completion of the laboratory stage of the project. The substantial conceptual and practical problems of vaccine development have been overcome.
The delivery component remains under development. However, the doctor is confident that this essential step will be overcome “in the near future.” He is very grateful for the generous support so far provided.
Human trials will then begin. Necessarily this may take an uncertain amount of time. I have communicated to the doctor the urgency of arriving at a viable treatment.
Commander of Sipo-SD Lange, Theresienstadt, Madagascar, Standartenfuhrer.
 “Operation Erfurt.” Erfurt is a city in Germany. Code names are most often randomly selected. However, at one time the addressee, Lange, commanded the security services in Erfurt. Nostalgia?