UNITED NATIONS (1994) "Sleeping child" by Wyspianski*. Set of 6 imperforate progressive proofs. Scott No 645, Yvert No 657. From the UN printer archives. Rare!
AVAILABLE AT $100
FRANCE (1963) The Fur Merchants*. Full sheet of trial color proofs, stained glass window in Chartres Cathedral". Scott No 1077, Yvert No 1399. Scan shows only part of sheet. Incredible!
AVAILABLE AT $1,200