Hi Bill
Glad to hear that you're interested in Swiss Army MV's. I thought I'd be the only one
You've got some good books, however there are more on that subject.
You're correct, the period '35 - '45 is not covered well. The Swiss Army was really undersourced at that time. E.g. the Swiss just had 24 Praga Tanks at the outbreak of war. Most MV's were bought after the war of American origine. My Grandad was a scrappie and scrapped thousands of them in the '60 - '80s.
Your pic shows as German Officer and probably an NCO sitting in front of an unknown truck. Definitely not belonging to the Swiss Army.
Greetings
Chris