 Pieter "Piet" Dijkgraaf, son of Jan Dijkgraaf and Elisabeth Schalk.Born 11 Dec 1934 Rotterdam, died 10 Jul 2008 Gouda, age 73 years Married 03 Mar 1960 Rotterdam (IJsselmonde), age 25 years (married 48 years) to:  Sonja Beukers, age by marriage 23 yearsBorn 18 Jun 1936 Barendrecht, died 09 Jun 2017, age 80 years Children: | |||