© Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn Hauptstrom (Main Stream) Joseph Beuys Accession Date: 05/01/06 Accession Number: F-BEUYS-106.067 1973 invitation card, stamped 6 3/4 x 9 5/8 in. (17.15 x 24.45 cm)