We have one object that Mr. Koestler has been involved with.

If you would like to cite this person in a Wikipedia article please use the following template:

<ref name=CH>{{cite web |url=https://collection.cooperhewitt.org/people/68775019/ |title=Mr. Koestler |author=Cooper Hewitt, Smithsonian Design Museum |accessdate=4 October 2022 |publisher=Smithsonian Institution}}</ref>