A monumental three-part illustrated history of ERMA, the Erfurter Maschinenfabrik. ERMA is best known for production of German small arms during the Second World War, including the MP 40 submachine gun, the Mauser K98 rifle, and the ERMA EMP.
This is partial text from the full article (usually with photos) at https://armorama.com/news/schiffer-the-erfurter-maschinenfabrik-erma-collection