With Kunsthandel P. de Boer, Amsterdam (as by Georg Keller, and signed with monogram; according to labels on the reverse).
The reverse of these copper plates are marked with the CK-monogram. This is to be found on plates painted by Antwerp artists active between c. 1603-1630. We are grateful to Prof. em. Dr. Jørgen Wadum of the Statens Museum for Kunst, Copenhagen for his help in identifying the copper mark.