They were not signed The title translates to "Place According to the Laws of Chance”.
Published in 1964 by Galerie Denise Rene, of Paris, for the rare exhibition catalogue "Hard Edge". Jean (Hans) Arp was one of several artists who contributed original silkscreens for this project (after their own paintings). Printed by the Imprimerie Mazarine on a sheet of thin wove paper without margins, and then tipped onto a support sheet (attached along the top edge).
Make enquiry to Robert Fontaine Gallery about this piece: