GenLias has a listing for Sara van Gelder as the wife of Simon van Delft. She died in Sobibor on 21-May-1943
Ovl 03-10-1949 Amersfoort #488: Sara van Gelder 50 jaar g. (not given) (Lazarus van Gelder en Rachel Topilowskij) ovl 21-05-1943 Sobibor. Weduwe Simon van Delft.
Sara is also listed on a Page of Testimony at Yad Vashem
Yad Vashem Page of Testimony submitted 08-Feb-2000 by Johan van Gelder, family:
Sara van Delft-van Gelder b. 19-08-1892 Groningen (Lazarus van Gelder and Rachel Topilowsky) married to Simon van Delft, residence Amersfort, deported 07-Dec-1942