Bob Henderson also co-authored a book in 1993: German Prisoners of War in Canada and Their Artifacts, 1940-1948

by Robert J. Henderson and C.M.V. Madsen
ISBN 0-9697888-0-0
SOFT COVER,  6" X 9",  203 pages

Details from AirMuseum.ca:

The definitive book on the history, activities and collectable artifacts of German Prisoners of War (with some Veteran Guard of Canada) ... from the Second World War.

Documented details including photographs, locations of branch camps, Labor Projcts, Military Hospitals, and Detention Centers. The book includes a special section on the collecting of artifacts relating to these Prisoners, including eighty photographs of "Collectibles" currently held in the Homefront Archives & Museum at Regina, Saskatchewan.

The book provides the historian, the researcher, and the colletor with details not found in any other publication!

There's a listing at Amazon but no copies available there or via AbeBooks.

Chris Madsen is also the author of another book on the period: The Royal Navy and German Naval Disarmament 1942-1947.