I think some of you may not be yet aware of the existence of a database concerning the roses hold at the Sangerhausen rosarium in Germany.
You can find a rose by its name (Sortnenname) by breeder (Name des Z
If you vant to restrict your search to rose, click on Detailsuche nach_Rosen and choose
Category (informal Kategorie)
Country of breeding (Land der Z
Great link Arnold, thanks!
Claire Grammerstorf is found at Sangerhausen, as far as I can see 
Bo
Thank you for the link. I’ve already enjoyed some searches which work very quickly.