"With his Invitation Project, conceptual art pioneer Robert Barry reflected on the growing global strategic partnerships between museums and galleries that developed in the 1960s and continued in the early 1970s. Barry asked his dealers to send an invite for each successive show at the next gallery. The project ended with Galleria Sperone sending an invitation card to the Paul Maenz gallery, thereby closing the circle". (da: "In & Out of Amsterdam: Travels in Conceptual Art, 1960–1976", ed. Christophe Cherix, 2009).