When in doubt, try "Universalfalz" holders. I have a similar camera, which is clearly marked "Rodenstock". But Rodenstock wasn't and isn't known as a camera producer, best guess is that someone else made a lot of cameras which were then marked (or not) for resale. No idea who, but they do tend to take Universalfalz holders - like (some) ICA, (some) Zeiss or (all) Voigtländer holders.
Oh - and Kodak holders don't fit any of my German 9x12cm plate cameras.