BRIDGET RILEY (b.1931) NINETEEN GREYS (D) (Schubert 8) screenprint in colours on card, signed,

BRIDGET RILEY (b.1931)'NINETEEN GREYS' (D)(Schubert 8)screenprint in colours on card, signed, titled, numbered and dated 1968 in pencil and inscribed "'Artist's Proof', aside from the edition of 7576.5cm x 76.5cmProvenance: Christies, Old Master, Modern and Contemporary prints including Property from the estate of Ernest Beyeler, 20 September 2011 (2361) Lot 286