I want to know the answer to the following question:
What was only incorporated into Layer III and not Layers I or II?
All the background I'm provided with is that "Under the chairmanship of Professor Musmann (University of Hannover) the editing of the standard was made under the responsibilities of Leon van de Kerkhof (Layer I) and Gerhard Stoll (Layer II).". Is that enough to answer the question?
Answer: no