I have found membership of the following organisations and websites to be very useful.
Working Groups, Societies and Clubs
The ArGe AM-POST is the German federal working group (Bundesarbeitsgemeinschaft) devoted to the study of the AM Post stamps and the postal history from the period of their validity. They publish a very detailed, high-quality journal about three times a year, which covers the latest discoveries and summarises ongoing research. They also publish handbooks on specific topics of interest to AM Post collectors.
The ArGe Deutsche Notmaßnahmen (DEUNOT) is the German federal working group dedicated to the study of the emergency and provisional measures adopted to enable the postal service to restart and function after World War 2. Key research topics covered in their journal include the censorship of civilian mail, cash franking, emergency and provisional postal stationery, improvised and adapted cancelling devices, the 1948 currency reform and the ‘postal wars’.
The Germany & Colonies Philatelic Society is one of the UK’s leading philatelic societies. They publish a journal four times per year, run a number of regional and topic-based face-to-face meetings throughout the UK, have an active packet circuit, run two or three postal auctions per year, have an active Zoom meeting group and hold a face-to-face members weekend at the start of October. It’s well worth joining if you are interested in any aspect of German philately and you want to meet and socialise with other people who share those interests.
The Allied Military Government Collectors Club is a US-based club for people who collect the stamps or postal history of any territory which was formerly occupied by an allied power. Membership provides access to digital copies of the entire back-catalogue of their journal and they hold regular Zoom meetings at UK-friendly times, so it’s worth joining even if you’re not based in the US. Currently, the club are working on producing a handbook to cover all of the major topics of interest to AMG collectors.
Online Forums
Philaseiten is a German-language forum which covers all aspects of worldwide philately. It contains a wealth of information about philately from the allied occupation zones and is a fantastic place to ask your own questions about this and any other philatelic topic.