I have 2 books reprints of 100 year old Bing catalogs but does something like that exist for Märklin or Pericaud? My pre ww2 items is of Bing and Märklin as well as Pericaud.
Books not in English work as well. I can use my phone to read those.
There is a whole series of hardbound books of Marklin catalog reprints numbered 1 to ? but I'm pretty sure these are now out-of-print.