If you seek a particular subject or if you have a particular question, here is a List of topics with references where you may find more information.
Please note that in English the radio programmes are only available as script, not as audio files.
The List of topics is available in the PDF format:
This is one single PDF file containing all main topics and all sub-topics. This file can be downloaded, saved and printed.
The “dota” materials in the manuals and radio programmes contain the following: