Sotheby's South Africa:
29/09/86; 1/12/86;
16/03/87; 22/06/87; 14/09/87; 23/11/87;
Stephan Welz & Co:
06/06/88; 29/08/88; 01/11/88;
05/06/89; 25/09/89; 20/11/89;
12/03/90; 11/06/90.