I found this link to historical footage at the French site of Sylvain Halgand. It is a very good supplement to the book of mr. Jehmlich
http://fr.youtube.com/watch?v=7k2ORvZmpmY
also, thre is a link Called "vario pancolar" where mr. Jehmlich as well as the praktiflex constructor is interviewed andadditional historical film clips are shown. Unfortunately the annoying adverts of youtube keep barging in if you are not careful to press the "back" button in time.
