 Ir. Johan Maxmilliaan "Jan" Dijkgraaf, son of Drs. Pieter Cornelis "Piet" Dijkgraaf and Priska Hildegarde Dorothea Exner.Born 24 Jul 1904 's-Gravenhage, died 21 Jul 1972 Rotterdam, 67 years, cremation 26 Jul 1972 Rotterdam. Occupation: werktuigkundig ingenieur/medewerker Unilever (o.a. Calvé Delft) Marriage notice 13 Feb 1931 Rotterdam. Married 24 Feb 1931 Wassenaar Divorced 22 Aug 1959 Wassenaar (28 years married) from:  Johanna "Han" Hendriks, daughter of Petrus Dirk Herko Hendriks, Ridder in de Orde van de Nederlandse Leeuw and Anje Bos.Born 31 Aug 1904 Groningen, died 15 Sep 1996 's-Gravenhage, 92 years Children: 2. Pieter Cornelis DijkgraafBorn 11 Nov 1937 's-Gravenhage, died 14 Nov 1937 's-Gravenhage 3. Otto DijkgraafBorn 26 Nov 1938 's-Gravenhage, died 05 Feb 1940 Wassenaar, 1 years 4.  Levenloos geboren DijkgraafBorn 23 Jan 1947 's-Gravenhage at 15:45 hour, died 23 Jan 1947 's-Gravenhage at 15:45 hour | |||
| 2nd marriage Ir. Johan Maxmilliaan "Jan" Dijkgraaf, son of Drs. Pieter Cornelis "Piet" Dijkgraaf and Priska Hildegarde Dorothea Exner. Married 02 Aug 1960 Rotterdam (11 years married) to: Maria Josephina Reinilda "Mia" Smeets, daughter of Peter Franciscus Smeets and Marie Nathalie Lambert.Born 11 Feb 1909 Antwerpen (B.), 114 years | |||