Its Gratz, I came up with several hits on Centaur ribbons in a quick search. Try
BTW - just for the edification of some, Graz has his shop undergoing some modifications and updates. He has run into a bit of a lag while he waits for his machines to receive the upgraded parts and get them installed. You may be in luck if he's got your new ribbons in stock already, but if not then you may be waiting for the machine upgrades to be completed and for him to start manufacturing again.
Same goes for his worldwide rapair/installation dealers. They are waiting for back ordered parts from him too.