Four auction catalogues, Christie's and Sotheby's, c. 1993-1997, the collection of M. Hubert De Givenchy, Christie's, Monaco, 4 December 1993, the Duke and Duchess of Windsor, sale 7000, Sotheby's, New York, 11-19 September 1997, Barbra Streisand collection, Christie's, New York, 3-4 March 1994, and the Estate, of Jacqueline Kennedy Onassis, Sotheby's, New York, Sale 6834, 23-26 April 1996 (4)