"[http://en.wikipedia.org/wiki/Estonian_Security_Police_and_SD, Birn, Ruth Bettina (2001). \"Collaboration with Nazi Germany in Eastern Europe: the Case of the Estonian Security Police\". Contemporary European History (Cambridge University Press)]" . "The Estonian Security Police and SD, or Sipo, was a security police force created by the Germans in 1942. The force integrated both Germans and Estonians within a unique structure mirroring the German Security Police. Following the German occupation in 1941, the German Army created police prefects based upon the old Estonian police model. In 1942 a new Security Police structure departments A-I to A-V, and an Estonian component, called\"Group B\" with corresponding departments was installed. The new Sipo force was designed by Martin Sandberger, leader of Einsatzkommando 1a. It was a unique joint structure that consisted of a German component, called\"Group A\" with. The Estonian Sipo wore the same uniforms as their German counterparts and attended Sipo schools in the Reich."@eng . "Sicherheitspolizei und SD in Estland, Gruppe B (Estnische Sicherheitspolizei)"@eng . .